WO 2020/079146 INE FORM II OF 2'-0-FUC0SYLLACT0SE, PROCESS PCT/EP2019/078209

PREPARATION, NUTRITIONAL, COSMETIC OR PHARMACEUTICAL

FORMULATION CONTAINING THE SAME

The present invention relates to the crystalline form of 2'-0-Fucosyllactose (2’-FL) with an ano- meric mixture of alpha:beta anomer in the range of 40:60 to 60:40. The present invention further relates to a process to obtain the new crystalline form. The present invention further relates to the use of the new crystalline form for nutritional applications, such as baby nutrition, specifically infant nutrition, and pharmaceutical applications, such as the improvement and/or maintenance of the healthy status of a human being, including gut health, stability of the immune system, and others as disclosed herein.

Background of the Invention

2'-Fucosyllactose (CAS No.: 41263-94-9: a-L-fucopyranosyl-(1 - 2)-0-3-D-galactopyranosyl- (1 -»4)-D-glucopyranose, hereinafter 2’-FL) is an oligosaccharide, which is found in relatively large quantities in breast milk. It has been variously reported that the 2'-FL present in breast milk causally reduces the risk of infection in newborns who are breast fed (see e.g. Weichert et al., Nutrition Research, 33 (2013), Volume 10, 831-838; Jantscher-Krenn et al., Minerva Pediatr. 2012, 64 (1) 83-99; Morrow et al., J. Pediatr. 145 (2004) 297-303). 2'-FL is therefore of particu- lar interest as a constituent of food supplements, particularly as additive for humanized milk products, especially for infant nutrition.

The molecular structure of 2'-0-Fucosyllactose (2’-FL) is shown in Figure 1.

The preparation of 2'-0-fucosyllactose by classical chemical or biochemical means has been variously described in the literature (for classic chemical means see e.g. US 5,438,124, WO 2010/070616, WO 2010/115934, WO 2010/1 15935, WO2016/038192 and WO2017/153452; for biochemical means see e.g. Drouillard et al. Angew. Chem. Int. Ed. 45, 1778 (2006), WO 2010/070104, WO 2012/007481 , WO 2012/097950, WO 2012/112777, WO 2013/139344, WO 2014/086373, WO 2015/188834 and WO 2016/095924).

Principally, the production of is 2’-FL by fermentation process using transformed microorgan- isms such as transformed E.coli is promising both for economic and environmental reasons. However, isolation of 2’-FL is tedious and usually requires

separating the supernatant containing the product by centrifugation,

adsorption of the product on a bed of activated charcoal that was washed with water to eliminate water-soluble contaminants like salts, amino acids and protein fragments, elution of the product with alcohol or aqueous alcohol, and

last not least, separation of 2'-FL from other carbohydrates like lactose and fucose by gel permeation chromatography or flesh chromatography on charcoal-celite beds.

The main drawback of this isolation method has been the need for chromatographic separation in order either to get the pure substance or to obtain at least a mixture that is enriched in the target compound but still contains undesired derivatives. Although repeated chromatographic separations can result in the improvement of the purity, its high cost and relatively long techno- logical time to handle the feed solution and the column packing, to carry out the separation and optionally to regenerate the packing, especially in large or industrial scale, can be disadvanta- geous and/or cumbersome.

Crystallization or recrystallization is principally a simple and cheap method for isolating a prod- uct from a reaction mixture and separating it from contaminations thereby obtaining a purified substance. Isolation or purification that uses crystallization may therefore render the whole technological process robust and cost-effective, thus it is principally advantageous and attrac- tive compared to other procedures. While crystallization of 2’-FL, which has been prepared by classical organic synthesis, is an efficient means for isolation or purification of 2’-FL, crystalliza- tion cannot be easily applied to 2’-FL, which has been prepared by non-classical organic syn- thesis, because the product obtained by fermentative production of 2'-FL contains a significant amount of by products, including in particular oligosaccharides other than 2’-FL, but also mono- saccharides. As these mono- and oligosaccharides have comparable polarities and, hence, comparable solubilities, they are difficult to separate by crystallization processes.

Kuhn et al. (Chem. Ber. 1956, page 2513) report that 2’-FL which has been purified by repeated chromatography does not readily crystallize but remains a syrup. The authors mention that few crystals of 2’-FI formed when leaving an aqueous solution of 2’-FI standing for a prolonged peri- od. Larger amounts of crystalline 2’-FL could be obtained only from solutions containing mix- tures of water with a considerable amount of organic solvents.

WO 2014/086373 describes a method for obtaining an oligosaccharide such as 2’-FL from a fermentation broth, which comprises freeze-drying of the fermentation broth, preferably after having removed proteins therefrom, to produce a dry powder, treating the dry powder with an aliphatic alcohol, such as methanol, to dissolve the oligosaccharide which is then crystallized from the alcoholic solution. The method is tedious as it requires previous freeze drying of the fermentation broth and the use of organic solvents.

WO 2015/188834 describes a method for crystallization of 2’-FL from an aqueous solution con- taining 2’-FL and a fucosylated oligosaccharide, such as difucosyllactose, which method corn- prises fermentative production of 2’-FL by using genetically modified cells having a recombinant gene that encodes a 1 ,2-fucosyltransferase, separating the supernatant from non-carbohydrate solids and contaminants and adding Ci-C4-alkanols in order to effect crystallization of 2’-FL.

WO 2016/095924 describes a method for crystallization of 2’-FL from an aqueous solution con- taining 2’-FL and a fucosylated oligosaccharide, such as difucosyllactose, which method corn- prises providing an aqueous solution of 2’-FL and the fucosylated oligosaccharide as described in WO 2015/188834 and addition of acetic acid to the aqueous solution in order to effect crystal- lization of 2’-FL.

WO 2014/009921 describes different polymorph forms of 2’-FL. While polymorph form B can be obtained by recrystallization of pure 2’-FL, e.g. pure polymorph form A, from water, purification of a 2’-FL containing raw material, which additionally contains considerable amounts of mono- or oligosaccharides different from 2’-FL is not described therein.

WO 2011/150939 A1 describes crystalline 2'-0-fucosyllactose polymorphs I and II in polycrys- talline or single crystal form. The disclosure describes that polymorph II may be 100 percent of either the alpha-anomeric form or 100 percent of the beta-anomeric form, or mixture thereof.

The disclosure however does not mention any specific mixture having a specific ratio of al- pha:beta anomers. Also not disclosed is any data showing the anomeric composition of the form ll-crystals said to be obtained.

WO 2013185780 A1 discloses a process for enhancing the stability of a a human milk oligosac- charide (HMO), or its precursor or blend when stored for extended periods at temperatures of 25 degrees C, comprising (a) providing the HMO or its precursor or blend in an aqueous solu- tion, and (b) then spray -drying the aqueous solution to remove at least 90% of the water and provide the HMO or its precursor or blend with a higher glass transition temperature (Tg) that is at least 40 degrees C. As the Tg is simply a known or at least measurable property of the corn- pound in question, this document simply claims the already known-spray-drying of HMO.

WO 2018164937 A1 discloses the production of crystalline 2-fucosyllactose involving concen- trating an aqueous starting solution comprising 2-fucosyllactose and at least one other carbohy- drate, to form a supersaturated solution, and precipitating 2-fucosyllactose crystal while subject- ing the supersaturated solution at a temperature greater than 60 degrees C. The supersaturated solution comprises optionally 1 wt.% or less organic solvent during the precipitation of the 2- fucosyllactose crystal.

Polymorphism is the tendency of a substance to crystallize in different crystalline forms. Differ- ent crystalline forms have different physical properties such as melting and sublimation temper- atures, solubility, dissolution rates, stability and hygroscopicity.

It has to be noted that the pure definition of polymorphism describes crystalline forms compris- ing of the same molecule. Pseudopolymorphism is some kind of extension to hydrates and solvates. However, even this definition is not broad enough for the description of anomers. In case of 2’-FL two anomers can be formed: a- and b-anomer. Both anomers are different mole- cules but can interchange into each other depending on the conditions and environment em ployed.

The following specific crystalline forms, i.e. polymorphs, of 2’-FL have been described in the literature: e.g. WO2014/009921 A2 (by Inalco) discloses three crystalline forms (form A: 1.5 wa- ter per 2’-FL molecule; form B: 2.5 water per 2’-FL molecule; form C anhydrate),

WO2014/069625A1 (by Kyowa Hakko) discloses two crystalline forms of 2’-FL (forms A and B similar as in the Inalco disclosure); WO2011/150939 (by Glycom) discloses two different anhy- drate forms (form I and form II). Besides the polymorphs, of course the amorphous form of 2’-FL is well known, as it can be ob- tained easily from 2’-FL-solutions by drying such as spray-drying, freeze-drying or any other kind of drying.

It makes sense to use the term“polymorphism” for the different crystalline forms of 2’-FL, know- ing that it is somehow extended. In the following“polymorphs” is also used as term for the crys- talline forms of varying a:3-anomeric ratio. The same extension to the definition of polymorphs was used by the authors of the three cited patent application of Inalco, Kyowa Hakko and Gly- com.

None of the documents cited above disclose the specific anomeric ratio of alpha- to beta- anomer of 2’-FL of polymorphic form II. All procedures disclosed do not or at least do not nec- essarily lead to such a crystalline form II of 2'-0-fucosyllactose having an alpha:beta anomeric ratio of from 40:60 to 60:40 or narrower including the 50:50-ratio.

Crystalline forms are however always associated with certain macroscopic properties such as crystal structure of the macroscopic crystal and crystal agglomerates, and thus have a signifi cant impact on macroscopic properties such as flowability, dissolution behavior such as the speed of dissolution, lumping tendency and the like. This is in principle known to a person of skill working in the field of organic chemistry and especially in the field of sugar chemistry but also in the field of physiologically active compounds for use in pharmaceutical, nutritional and agrochemical environments and formulations. Thus, an improvement in the stability of crystal structure is highly desirable, even if only slight improvements may be achieved, as the amount of a compound in question to be produced and/or the value of such compound usually is ex tremely high; thus, even slight improvements may result in significant advantages of the product and/or high cost savings for the producer and/or the user of such compound.

Thus, there was still a need for an improved crystal form of 2’-FL having a better property pro- file, such as a greater stability, compared to all previously known crystalline forms.

Therefore, the present invention relates to

a) a crystalline form II of 2'-0-Fucosyllactose ( 2’-FL) having an alpha:beta anomeric ratio of from 40:60 to 60:40;

b) a process of crystallizing crystalline form II of 2’-FL having an alpha:beta anomeric ratio of from 40:60 to 60:40;

c) a crystalline form II of 2’-FL having an alpha:beta anomeric ratio of from 40:60 to 60:40 obtainable by the inventive process;

d) a crystalline form II of 2’-FL having an alpha:beta anomeric ratio of from 40:60 to 60:40, with a purity of at least 98 percent by weight based on total saccharides, and/or a residual solvent content of organic solvents of at most 0,5 percent by weight based on total solids; e) a nutritional formulation, specifically infant formula, or pharmaceutical formulation, corn- prising the claimed crystalline forms of a), c) or d) or obtainable from b). f) the use of the claimed crystalline form of a), c) or d) or obtainable from b) for the prepara- tion of

a. a nutritional formulation to booster the development and/or improvement of the

brain, the immune system, intestine microbiotic environment of an infant or baby; and/or the improvement and/or maintenance of the brain, the immune system, intes- tine microbiotic environment, general physical ability and/or the resistency against pathogenic attacks within a human child or adult, or

b. a cosmetic formulation for the maintenance and/or improvement of the skin such as elasticity, resistency against pathogenic attacks and/or the microbiota of the skin; or c. a pharmaceutical formulation for the treatment and/or prevention of diseases or dis- orders of the brain, the immune system, the microbiotic environment of the skin and/or the intestines, the general physical ability; and/or of pathogenic attacks within humans or animals.

g) a nutritional preparation comprising the claimed nutritional formulation according e) corn- prising water and optional at least one further suitable ingredient selected from lactose, mono-, di- and/or oligosaccharides (besides 2’-FL), vitamins, minerals, pre-biotics, pro- biotics wherein the ratio of alpha:beta anomers of 2'-0-Fucosyl lactose remains stable, and wherein the preparation is not mammalian milk; and

h) a method of treating a nutritional preparation according to claim 16 or 17, wherein the preparation is kept at elevated temperature of at least 30°C for a period of at least 3 minutes.

Thus, specific embodiments of the present invention are as follows:

Embodiment 1 : Crystalline form II of 2'-0-Fucosyl lactose (2’-FL) having an alpha:beta anomeric ratio of from 40:60 to 60:40.

Embodiment 2: Crystalline form of embodiment 1 , whereas the a^-anomeric ratio is from 40:50 to 50:40.

Embodiment 3: Crystalline form of embodiment 1 , whereas the a^-anomeric ratio is from 42:50 to 50:42.

Embodiment 4: Crystalline form of embodiment 1 , whereas the a:3-anomeric ratio is from 45:50 to 50:45, preferably 48:50 to 50:48.

Embodiment 5: Crystalline form of embodiment 1 , whereas the a^-anomeric ratio is about 50:50.

Embodiment 6: Crystalline form of embodiment 1 , whereas the a^-anomeric ratio is exactly 50:50.

Embodiment 7: Process of crystallizing crystalline form II of any of the embodiments 1 to 6. Embodiment 8: Process according to embodiment 7, wherein the crystallization solution is kept at a sufficient time for reaching an equilibrium of two the anomeric forms at a temperature of preferably at least 20 °C before the crystallization is initiated or starts by itself upon induction of crystallization conditions.

Embodiment 9: Process according to embodiment 7 or 8 wherein the crystallization is initiated by lowering the temperature and/or removing part of the solvent of the crystallization and/or adding seed crystals.

Embodiment 10: Process according to any of embodiments 7 to 9 wherein the process encom- passes further steps of separating the crystals from the mother liquor, washing the crystals, re- moving residual solvent from the washed crystals, and optionally a further step of exposing the crystals to vapor of water under conditions suitable to further reduce the content of residual or ganic residues such as organic solvents.

Embodiment 1 1 : Crystalline form of any of the embodiments 1 to 6 obtained by the process of any of the embodiments 7 to 10.

Embodiment 12: Crystalline form II of 2'-0-Fucosyllactose having an alpha:beta anomeric ratio of from 40:60 to 60:40, preferably from 45:55 to 55:45, more preferably from 40:52 to 52:48, even more preferably from about 50:50 such as exactly 50:50, with a purity of 2’-FL of at least 98, preferably at least 99, even more preferably at least 99,5 percent by weight based on total saccharides, and a 2’-FL-content of at least 90 percent, preferably at least 92, more preferably at least 94, even more preferably at least 95, and most preferably at least 96 percent by weight based on total solids such as 97, 98 or even 99 or more and every value in between, and/or a residual solvent content of organic solvents of at most 0,5, preferably at most 0,1 , more pre- ferred at most 0,05, even more preferred at most 0,01 percent by weight based on total solid.

Embodiment 13: Nutritional formulation, specifically infant formula, or pharmaceutical formula- tion, comprising the crystalline form of any of the embodiments 1 to 6 or 11 or 12 or obtained from the process according to embodiment 7 to 10.

Embodiment 14: Use of crystalline form according to any of the embodiments 1 to 6 or 1 1 or 12 or obtained from the process according to any of the embodiments 7 to 10 for the preparation of

A) a nutritional formulation

a. to booster the development and/or improvement of the brain, the immune system, intestine microbiotic environment of an infant or baby; and/or

b. the improvement and/or maintenance of the brain, the immune system, intestine mi- crobiotic environment, general physical ability and/or the resistency against patho- genic attacks within a human child or adult, or

B) a cosmetic formulation for the maintenance and/or improvement of the skin such as elas- ticity, resistency against pathogenic attacks and/or the microbiota of the skin; or C) a pharmaceutical formulation for the treatment and/or prevention of diseases or disorders of the brain, the immune system, the microbiotic environment of the skin and/or the intes- tines, the general physical ability; and/or of pathogenic attacks within humans or animals.

Embodiment 15: Formulation according to embodiment 13 having an improved storage stability when compared to formulations comprising other crystalline forms of 2'-0-Fucosyllactose than the crystalline form of any of the embodiments 1 to 6 or 1 1 or 12 or obtained from the process according to any of the embodiments 7 to 10.

Embodiment 16: Nutritional preparation comprising the formulation according to embodiment 13 or 15, comprising water and optional at least one further suitable ingredient selected from lac- tose, mono-, di- and/or oligosaccharides, vitamins, minerals, pre-biotics, pro-biotics, wherein the ratio of alpha:beta anomers of 2'-0-Fucosyllactose remains stable, and wherein the preparation is not mammalian milk.

Embodiment 17: Nutritional preparation according to embodiment 16, wherein the a^-anomeric ratio is about 50:50, preferably 50:50.

Embodiment 18: Method of treating a nutritional preparation according to embodiment 16 or 17, wherein the preparation is kept at elevated temperature of at least 30°C, preferably at least 35°C, for a period of at least 3, preferably 5, more preferably at least 7 minutes.

Detailed Description of the Invention

Here and in the complete description the terms 2’-FL and 2'-fucosyllactose are used synony- mously and refer to a-L-fucopyranosyl-(1 - 2)-0-3-D-galactopyranosyl-(1->4)-D-glucopyranose, including the a- and b-anomers and mixtures thereof.

The terms a:b anomeric ratio and alpha:beta anomeric ratio are used interchangeably through- out. The singular form of a word encompasses also the plural and plural encompasses singular forms.

The term“2’-FL raw material” as used herein refers to an oligosaccharide composition, which contains 2'-FL as a main constituent, in particular in an amount of at least 70 % by weight, and a considerable amount, i.e. more than 0.5 by weight, in particular at least 2 % by weight, and es- pecially at least 5 % by weight such as 6, 7, 8, 9 or even 10 percent by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligo saccharides different from 2’-fucosyllactose. In particular, the 2’-FL raw material from which crystalline 2’-FL is obtained by the method of the invention contains:

70 to 99.5 % by weight, in particular 75 to 95 % by weight, especially 78 to 92 % by weight, based on the total amount of mono- and oligosaccharides in the raw material, of 2'-FL, and 0.5 to 30 % by weight, in particular 5 to 25 % by weight, especially 8 to 22 % by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligosaccharides different from 2’-fucosyllactose.

Typical mono- and oligosaccharides contained in the 2’-FL raw material, which are different from 2’-fucosyllactose, include but are not limited to lactose, fucosylated lactose other than 2’- FL such as di-fucosyl lactose, fucose, galactose, glucose, lactulose and fucosylated lactulose. These mono- and oligosaccharides are hereinafter termed“carbohydrate impurities or byprod- ucts”.

The term“fucosylated lactose other than 2’-FL” as used herein includes any monofucosylated lactose other than 2’-FL. The term“fucosylated lactose other than 2’-FL” also includes any poly- fucosylated lactose, in particular a difucosylated lactose which is also termed“difucosyllactose”, such as 2,2’-0-difucosyllactose or 2’,3-O-difucosyllactose.

Likewise, the term“fucosylated lactulose” used herein includes any monofucosylated lactulose and polyfucosylated lactulose, i.e. lactulose, which is fucosylated on the galactose moiety of lactulose by 1 or more, e.g. 1 or 2 fucose moieties.

The aforementioned carbohydrate impurities or byproducts may be formed during fermentation or under post-fermentation conditions. For example, fucosylated lactose other than 2’-FL may be formed as a result of a deficient, defective or impaired fucosylation other than an a-1 ,2- fucosylation on the galactose moiety of lactose, or of a fucose migration of 2’-FL under the fer- mentation or post-fermentation conditions or of fucose hydrolysis from multi-fucosylated lactose. Other carbohydrate impurities or byproducts may be formed by rearrangement such as lactu- lose and fucosylated lactulose or by hydrolysis such as fucose, glucose, galactose and lactose or may be unconsumed starting material, such as glucose or lactose.

In particular, the 2’-FL raw material contains at least one fucosylated lactose other than 2’-FL, in particular difucosyllactose. In particular, the amount of fucosylated lactose is in the range from 0.5 to 10 % by weight, based on the weight of mono- and oligosaccharides contained in the 2’- FL raw material. In particular, the 2’-FL raw material also contains at least one of lactulose and fucosylated lactulose or a mixture of both. In particular, the total amount of lactulose and fuco- sylated lactulose is in the range from 0.5 to 10 % by weight, based on the weight of mono- and oligosaccharides contained in the 2’-FL raw material.

Embodiments 1 to 6: Crystalline form II of 2'-0-Fucosyllactose ( 2’-FL)

The present invention relates to a crystalline form II of 2'-0-Fucosyllactose ( 2’-FL) having an alpha:beta anomeric ratio of from 40:60 to 60:40, preferably from 40:50 to 50:40, more prefera- bly from 42:50 to 50:42, even more preferably from 45:50 to 50:45, such as 48:50 to 50:48, about 50:50 and exactly 50:50. The crystals of the form II of 2’-FL are known from the disclosure of e.g. WO 201 1150939 A1. However, the disclosure only describes that polymorph II may be 100 percent of either the al- pha-anomeric form or 100 percent of the beta-anomeric form, or mixture thereof albeit with un- specific anomeric-ratio. Also not disclosed is any data showing the anomeric composition of the form ll-crystals said to be obtained.

A comparison of the data presented in the three above cited patent application of Inalco, Kyowa Hakko and Glycom is listed in Table 1 supplemented with the polymorph of the present inven- tion.

Table 1 : Comparison of 2’-FL polymorphic forms; ^* : data according to SCXRD, ⁺ : data ac- cording to NMR; ^** data from the cited reference

crystalline form hydrate/anhydrate a anomer b anomer SCXRD

I anhydrate 100 0 WO2011/150939

(> 70) ⁺ (< 30) ⁺

anhydrate 100 0 0 100 No data disclosed in

WO2011/150939

II (of the present anhydrate 50 50 Presented herein invention)

Crystalline form II of 2'-0-Fucosyllactose ( 2’-FL) is in principle described for example in WO201 1/150939. The data presented consists of powder X-ray diffraction data, IR data, DSC data and HPLC assay. It is said that“the crystalline 2-FL polymorph II can be considered as an a:b mixture of a- and b-anomers or even pure form of one of the anomers”, but no data is pre- sented nor a method to determine the a:b ratio is described.

The present invention however is able to directly prepare a crystalline form II of 2'-0- Fucosyllactose ( 2’-FL) having an alpha:beta anomeric ratio of from 40:60 to 60:40 up until as narrow as 50:50, with an experiment showing that about 50:50 (i.e. 50:49,505) can be prepared by the process disclosed herein.

The crystalline form II of 2’-FL of the present invention having the herein defined alpha:beta anomeric ratio shows the characteristic XRPD-peaks as previously disclosed, e.g. its character istic reflections in an X-ray powder diffractogram, in particular the following reflections, quoted as 20 values: 16.98 ± 0.2°, 13.65 ± 0.2° and 18.32 ± 0.2°, (at 25°C and Cu-Ka radiation).

Embodiments 7 to 10: Process of crystallizing crystalline form II of any of the embodiments 1 to 6.

The present invention also discloses a process for crystallizing form II of 2'-0-Fucosyllactose ( 2’-FL) having an alpha:beta anomeric ratio of from 40:60 to 60:40, preferably from 40:50 to 50:40, more preferably from 42:50 to 50:42, even more preferably from 45:50 to 50:45, such as 48:50 to 50:48, about 50:50 and exactly 50:50. It has been found that claimed form II of 2'-FL with the specific anomeric ratio can be efficiently and reliably crystallized from an aqueous solution of a 2'-FL raw material, which contains con- siderable amounts of mono- and oligosaccharides other than 2'-FL, by maintaining the solution for a sufficient time at elevated temperatures of preferably at least 20 °C to and then inducing conditions of controlled supersaturation in the aqueous solution and thereby effecting selective crystallization of 2'-FL Inducing conditions of controlled supersaturation in the aqueous solution of 2'-FL raw material allows for efficient crystallization without the use of considerable amounts of organic solvents during crystallization. This is quite surprising, because 2'-FL is highly soluble in water and even pure 2’-FL hardly crystallizes from water; the considerable amounts of mono- and oligosaccharides contained in the 2'-FL raw material should further hamper crystallization of 2’-FL. Specifically the crystallization procedure is set up so to keep the crystallization solution at a sufficient time for reaching an equilibrium of two the anomeric forms at a temperature of pref- erably at least 20 °C before the crystallization is initiated or starts by itself upon induction of crystallization conditions.

“Sufficient” time depends on the actual temperature employed and the concentration of the 2’- FL in the crystallization liquor, e.g. on the viscosity of the liquor, and the thermal energy within the solution. Thus, increasing the temperature obviously lowers the time needed for reaching the equilibrium, whereas increasing the viscosity increases the time needed due to impeding the transduction of thermal energy throughout the whole sample.

Adding organic solvents, that are non-solvents for 2’-FL reduce the solubility of 2’-FL and can also influence the time to reach equilibrium.

Hence, as general principle care has to be taken to allow for a sufficient time at the conditions chosen to allow the system to reach the equilibrium or go as close as desired. As there are many variables, no general guideline can be given for all circumstances. However, the exam- ples disclosed herein serve as guideline.

In fact, when the equilibrium has been reached and the present anomeric ratio of alpha to beta can be easily confirmed using e.g. NMR-measurements and calculations. Thus, if the time was “sufficient” can be easily determined for each individual case of crystallization, which can then serve as guideline for the next crystallization. If not the optimum alpha:beta anomeric ratio of 50:50 is desired, of course shorter times can be chosen.

Good to optimum properties of the inventive crystalline form II have been found with alpha:beta anomeric ratios of from 60:40 to 40:60, with narrower ranges showing at least slightly improved results compared to the broader ranges, and optimal results at close to 50:50 such as 48:50, 49:50, or about 50:50.

“About 50:50” means that the ratio is very close to that value but not numerically exactly that value, as for example a ratios of 50:49,5, 49,5:50 and the like will considered to meet the defini- tion of“about 50:50” within this present invention, and thus encompassed within the claimed subject matter.

The crystallization process of the present invention is“initiated” by lowering the temperature and/or removing part of the solvent of the crystallization and/or adding seed crystals and/or add- ing a solvent which is a non-solvent for 2’-FL (termed“anti-solvent” within this invention) or which at least lowers the solubility of 2’-FL.

The temperature may be lowered gradually or continuously, preferably in small steps at not to large increments or continuously at not too short time intervals.

Anti-solvents may be added continuously or stepwise to initiate crystallization.

Anti-solvent and/or solvent may be removed by evaporation using any suitable means known for this to initiate crystallization.

Stirring can also help to initiate crystallization, especially for super-saturated conditions.

There are a number of ways known in the art suitable to initiate crystallization and in principle all of them are suitable.

Typical procedures for such crystallization are well known in the art.

The preferred crystallization procedure is as follows:

The process of crystallizing crystalline form II of 2’-fu cosy I lactose from a 2'-FL raw material, which contains 2'-FL as a main constituent and optionally one or more mono- or oligosaccha- rides different from 2’-FL, where the process comprises

a) providing a solution of the 2'-FL raw material in water, which does not contain more than 5 % by weight of organic solvents, based on the total amount of water;

b) effecting the crystallization of 2’-FL from the solution provided in step a) by inducing condi- tions of a controlled supersaturation in the solution, adding an anti-solvent, stirring, lower- ing the temperature and/or evaporation of solvent; and

c) separating crystalline 2'-FL from the mother liquor,

and where during the induction of the crystallization in step b) not more than 5 % by weight of organic solvents are present, based on the total amount of water present during step b).

The process of the present invention is associated with several benefits. It allows efficient sepa- ration of 2’-FL from the other oligosaccharides, thereby obtaining 2’-FL in high yield and high purity of frequently more than 93 %, in particular more than 95 %, more preferably more than 98%, and even more preferably 99% or more, based on organic matter in the crystalline 2’-FL.

In particular, the process does not require the extensive use of organic solvents during crystal I i- zation and, therefore, the risk that the crystalline 2’-FI contains significant amounts of entrapped solvent is minimized. By the process of the invention substantially pure crystalline 2’-FL having an alpha:beta ano- meric ratio of from 40:60 to 60:40, preferably from 40:50 to 50:40, more preferably from 42:50 to 50:42, even more preferably from 45:50 to 50:45, such as 48:50 to 50:48, about 50:50 and ex- actly 50:50, is obtained in the form of compact crystals having usually an aspect ratio (ratio of length to thickness) of generally lower than 10 : 1 , in particular lower than 5 : 1 or even lower than 2 : 1. The average particle size of the crystalline material is generally in the range from 0.2 to 1.5 mm, in particular from 0.3 to 1.0 mm, where the average particle size is the weight aver- age particle size as determined by light scattering methods or sieving in accordance with DIN 66165-2:1987-04. Preferably, the crystalline 2’-FL obtained by the process of the invention con- tains in particular less than 10% by weight of particles having a particle size of below 100 pm.

In particular, and even more so when the use of organic solvents is not desired, the crystalline form II 2’-FL having the claimed specific anomeric ratio will be obtained if the crystallization of 2’-FL is effected at a temperature of above 60°C, in particular at a temperature of above 62°C.

Therefore the present invention also relates to a process for obtaining crystalline form II of 2’-FL having an alpha:beta anomeric ratio of from 40:60 to 60:40, preferably from 40:50 to 50:40, more preferably from 42:50 to 50:42, even more preferably from 45:50 to 50:45, such as 48:50 to 50:48, about 50:50 and exactly 50:50, from a 2’-FL raw material as defined herein, which process comprises performing the process for obtaining crystalline 2’-FL as described herein, provided that the crystallization solution is maintained for a sufficient time at elevated tempera- tures of preferably at least 20 °C and - and especially when the use of organic solvents is not desired - then crystallization is effected at a temperature of above 60°C, in particular of above 62°C to obtain the crystalline form II of 2’-fucosyllactose having the specified anomeric ratio.

A generally suitable crystallization process is described in the following, provided that the step of maintaining the crystallization solution for a sufficient time at elevated temperatures of prefer- ably at least 20 °C before crystallization is effected is inserted into the described procedure:

In a first step a) of the process of the invention, an aqueous solution of 2’-FL raw material is provided which is in then maintained for a sufficient time at elevated temperatures of preferably at least 20 °C, and then subjected to a crystallization in the second step b) under conditions of controlled supersaturation. Principally, any aqueous solution of 2’-FL raw material, which does not contain more than 5 % by weight of organic solvents, based on the amount of water con- tained therein, can be utilized in the method of the invention. In one embodiment such organic solvent is or comprises an anti-solvent.

It is preferable for the invention that the aqueous solution of the 2’-FL raw material provided in step a) and which is maintained for a sufficient time at elevated temperatures of preferably at least 20 °C, and then subjected to the crystallization in step b) and also the water present during step b) does not contain considerable amounts of organic solvents. Preferably, the concentra- tion of organic solvents in the solution provided in step a) does not exceed 5 % by weight, in particular not exceed 2 % and especially not exceed 1 % by weight, based on the water con- tained in the solution provided in step a). Furthermore, the concentration of organic solvents in the water which is present during step b) does not exceed 5 % by weight, in particular not ex- ceed 2 % and especially not exceed 1 % by weight, based on the water present during step b).

In this context, the term“organic solvent” includes any organic compound, which has a boiling point at normal pressure in the range from 30 to 250°C and includes, e.g. organic alcohols, in particular Ci-C4-alkanols and Ci-C ₄ -alkanoic acids and any other organic compounds commonly used in the field of organic chemistry, in particular in the field of carbohydrate chemistry.

The aqueous solution may be an aqueous solution obtained from a biochemical process or from a conventional, i.e. chemical process.

The aqueous solution of the 2’-FL raw material utilized in the method of the invention is prefera- bly obtained from a biochemical process, such as a process, where 2’-FL is obtained by an en- zymatic biocatalytic fucosylation of lactose or by a fermentation, as described e.g. in Drouillard et al. Angew. Chem. Int. Ed. 45, 1778 (2006), WO 2010/070104, WO 2012/007481 , WO

2012/097950, WO 2012/112777, WO 2013/139344, WO 2014/086373, WO 2015/188834 and WO 2016/095924.

The fermentation broth usually contains in the supernatant of the culture medium at least 25 g/L of 2’-FL and may contain up to 120 g/L of 2’-FL or even more than 120 g/L of 2’-FL. In addition, the supernatant may also contain DFL, typically in amounts of about 1 ,5 to 20 % by weight, rela- tive to 2'-FL. The 2'-FL/DFL-mixture optionally contains fucosylated lactulose, which is produced in the culture medium, and/or lactose as unconsumed acceptor or further mono- or oligosaccha- rides.

If the aqueous solution of the raw material utilized in the process of the invention is obtained from a biochemical process, in particular from a fermentation, the obtained aqueous solution is frequently subjected to a post treatment prior to crystallization.

Such a post treatment may comprise a conventional demineralization step during which miner- als, salts and other charged molecules are extracted from the aqueous solution before crystal I i- zation. The demineralization can be conducted by using conventional ion exchange resins, namely passing the aqueous solution through a cation exchange resin in H ⁺ -form and an anion exchange resin in free base form. The cation exchange resin is preferably a strong exchanger, and the anion exchange resin is preferably a weak exchanger. The ion exchange resins, be- sides removing salts and charged molecules from the solution, can physically adsorb proteins, DNA and colorizing/caramel bodies that optionally left in the solution after previous purification steps. Alternatively, the demineralization can be conducted by means of a conventional electro- dialysis. Additionally, adsorbents such as activated carbon may be optionally employed to re- move colorizing compounds from the aqueous solution.

In some cases, it may be desirable to selectively remove some components of the aqueous solution of 2’-FL before crystallization. This may be achieved using different types of chromatog- raphy such as elution chromatography with or without a recycle loop or with continuous chroma- tographic processes such as simulated moving bed chromatography (SMB) including the varia- tions thereof with asynchronous switching of the inlets and the outlets and/or variations of flow rates and/or feed concentration during a switch interval. Methods for using SMB for purification of aqueous solutions of oligosaccharides, such as 2’-FL, obtained from a fermentation have been described e.g. by T. Eiwegger et al., Pediatric Research, Vol. 56 (2004), pp. 536 - 540,

CN 102676604 and EP2857410, which can be applied by analogy for removing some compo- nents of the aqueous solution of 2’-FL before crystallization. A review of suitable methods for performing SMB can be found in M. Ottens et al.,“Advances in process chromatography and application”, Chapter 4.4.3, pp. 132 - 135, Woodhead Publishing Limited 2010 and the literature cited therein.

The solution obtained by any above ways can then be concentrated by either a conventional evaporation step or a conventional nanofiltration step, including ultrafiltration and diafiltration. Also, a Microfiltration may be incorporated to remove proteins and macromolecules. A further final (“sterile”) filtration before crystallization may be included to remove microbial contaminants. It is beneficial, if the aqueous solution of 2'-FL raw material, which is provided in step a), is es- sentially free of water-insoluble solid material, i.e. the amount of water-insoluble material is less than 5000 ppm, in particular less than 1000 ppm, based on the 2’-FL contained therein, or at most 3000 ppm, in particular at most 1000 ppm, based on the weight of the aqueous solution of the 2’-FL raw material. Therefore, post treatment will preferably comprise a conventional clarifi- cation step. By this clarification step, cells fragments (debris) and proteins after fermentation are removed. Clarification is preferably prior to the charcoal treatment described below. The clarifi cation can be done in a conventional manner, e.g. by sedimentation in centrifuge producing a clarified or partially clarified supernatant solution. Alternatively, the fermentation broth can be subjected to filtration step, e.g. to a micro-filtration or ultrafiltration, prior to subjecting it to the crystallization of step b). For example, ultrafiltration is performed in a conventional manner and removes high molecular weight components. The semipermeable membrane used for ultrafil- trating a 2'-FL fermentation broth can suitably have a cut-off of 5- 50 kDa, preferably 10-25 kDa, more preferably around 15 kDa. Depending on the characteristics of the fermentation broth to be clarified, a combination of higher and lower cut off-membranes (in this order) within the above given range may be employed. Optionally, centrifugation or ultrafiltration can be followed by nanofiltration, during which the aqueous solution containing 2'-FL and carbohydrate by- products is concentrated in a conventional manner before it is treated with charcoal. In this nan- ofiltration step, its membrane can have a pore size that ensures retention of 2'-FL having a mo- lecular weight of 488; so, typically, a 200-300 Da cut off membrane can be used.

In addition, post-treatment can further comprise a conventional charcoal treatment, which is preferably conducted before the demineralization step, in order to remove color bodies and op- tionally water-soluble bio-junk optionally left from previous purification steps. The carbohydrate compounds have strong affinity to be adsorbed on charcoal in aqueous medium; thus, water- soluble contaminants can be easily washed away with (distilled, preferably food-grade) water. The carbohydrates can then be eluted from the charcoal bed with alcohol or aqueous alcohol. The solution provided in step a) is then maintained for a sufficient time at elevated temperatures of preferably at least 20 °C, more preferably at least 30°C, even more preferably at least 40°C, such as 50, 55, 60, 62, 65 or higher and every value in between, but does preferably not exceed 95 °C, more preferably not exceed 90 °C, and may be lower such as 85, 80, 75, 70 etc. and every value in between.

In step b) the crystallization of 2’-FL is effected by inducing conditions of a controlled supersatu- ration in the solution the 2’-FL raw material.

The concentration of 2’-FL in the aqueous solution, which is subjected to crystallization in step b), may generally vary from 500 to 750 g/L, depending on the temperature of the aqueous solu- tion. Frequently, the total concentration of carbohydrates, i.e. 2’-FL and mono- and oligosaccha- rides different from 2’-FL is in the range from 510 to 950 g/L.

Frequently, a dilute solution having a concentration of 2’-FL of at most 500 g/L, e.g. in the range from 25 to 450 g/L is provided in step a), which is then subjected to a concentration step, e.g. by evaporation of water, to a concentration of 2’-FL, where crystallization may occur, which is in particular in the range from 500 to 750 g/L, in particular from 510 to 720 g/L.

The concentration of the dilute solution to the desired concentration range for crystallization and the crystallization may be conducted in a single step, i.e. in the crystallization apparatus. It is also possible to perform a pre-concentration step first, where water is removed by evaporation, until a concentration 2’-FL is achieved, which is still below the solubility of 2’-FL under the equi- librium conditions. Then, this solution is introduced into the crystallization apparatus and in the thus concentrated conditions of controlled supersaturation are induced. The concentration of 2’- FL which corresponds to the solubility under conditions of equilibrium is also termed the equilib- rium concentration or equilibrium solubility c ^* under the given conditions. As mentioned above, the concentration of 2’-FL in the solution, where conditions of controlled supersaturation are induced are typically in the range from 500 to 750 g/L.

For the purpose of the process to obtain the claimed crystalline form II having the specified anomeric ratio, it has been found beneficial, if the concentration of 2’-FL in the aqueous solution of the 2’-FL raw material, which is subjected to crystallization in step b), is above 630 g/L, in particular above 650 g/L.

Inducing conditions of controlled supersaturation at the given conditions ensures that the de- si red crystalline form II having the specified anomeric ratio can be selectively crystallized from the aqueous solution of the 2’-FL raw material.

“Controlled supersaturation” means that during crystallization the degree of supersaturation does not exceed a value, where uncontrolled, i.e. spontaneous crystallization does occur. The degree of supersaturation is understood as the ratio of the actual concentration c of dissolved 2’-FL during crystallization to the equilibrium solubility c ^* of 2’-FL in water at the given condi- tions, i.e. the ratio c : c ^* . In particular the ratio c : c ^* will not exceed a value of 1.5 : 1 , in particu- lar a value of 1.3 : 1 , more particular a value of 1.2 : 1 , especially a value of 1.15 : 1. Apparently, supersaturation requires that the ratio c : c ^* exceeds the state of the thermodynamic equilibri um, i.e. the state where the ratio c : c ^* is 1 , i.e. that c : c ^* has a value of more than 1 : 1. The value of more than 1 : 1 indicates e.g. a value of 1.00001 : 1 , 1.0005 : 1 , 1.0001 : 1 , 1.0005 : 1 ,

1.001 : 1 or 1.0002 : 1 , in particular a value in the range of 1.00001 to 1.002 : 1. The equilibrium concentration c ^* of 2’-FL in water at a given temperature or pressure is known or can be deter- mined by routine experiments. The actual concentration of dissolved 2’-FL in water can be cal- culated utilizing the concentration of 2’-FL in the aqueous solution, the amount of 2’-FL fed to the crystallization apparatus, the amount of water removed and the amount of crystallized 2’-FL. The actual concentration of the solution or suspension may also be determined experimentally, e.g. by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) or by density measurement.

The concentration of dissolved 2’-FL and thus the degree of supersaturation is usually adjusted by removing water from the aqueous solution of the 2’-FL raw material, i.e. by increasing the concentration of 2’-FL under conditions of the crystallization, and/or by cooling, i.e. by decreas- ing the solubility of 2’-FL under conditions of crystallization, and in particular by evaporation or by a combination of both. For achieving or maintaining conditions of supersaturation, water is preferably removed by evaporation. In particular, conditions of supersaturation are induced and maintained by evaporation of water or by combined evaporation/cooling.

Preferably, water is removed by evaporation under reduced pressure. Preferably, water is evaporated at pressures in the range from 10 to 900 mbar, in particular in the range from 50 to 800 mbar.

Preferably, evaporation is performed at a temperature of at least 20°C, in particular at least 25°C, more particularly at least 30°C, especially at least 35°C. Generally, the temperature will not exceed 105°C, in particular not exceed 100°C or 95°C. The temperature, where evaporation is performed, will also depend on the type of polymorph produced. For obtaining the desired crystalline form II having the specified anomeric ratio the aqueous solution of the 2’-FL raw ma terial is usually concentrated a temperature in the range from above 60 to 105°C, in particular from 62 to 100°C or from 62 to 95°C.

Evaporation of water may be achieved by conventional means using any equipment which al- lows for removal of water by distillation. The type of apparatus will depend in a known manner from whether water is removed during pre-concentration or for inducing conditions of controlled supersaturation and also whether the crystallization is operated discontinuously, i.e. batch or semi-batch, or continuously.

For inducing conditions of supersaturation by evaporation of water in a batch or semi-batch op- erated crystallization a simple vessel may be used, where the necessary heat is transferred by a heating device, e.g. by a double jacket, by heating elements in the vessel, by an external pumping loop with a heat exchanger or by a combination of these apparatuses. If the crystalliza- tion is performed in a continuous manner, a continuously operating crystallization apparatus will be used for inducing conditions of supersaturation by evaporation of water, such as stirred tank vessels, stirred tank vessels with guiding pipe, forced circulation crystallizers (FC), draft tube baffle crystallizers (DTB) or Oslo crystallizers. The evaporators may be heated with convention- al heating media such as heating oils or heating steam, including steam from a steam network or steam provided in the process of the present invention by vapor recompression.

Evaporation of water in the pre-concentration step may be achieved by conventional means using any equipment which allows for removal of water by distillation, such stirred tank vessels, thin film evaporators, falling film evaporator and helical tube evaporators. Preferably, evapora- tion of water in the pre-concentration step is achieved by means of a falling-film evaporator, preferably using heating steam obtained by mechanical vapor recompression. Mechanical vapor recompression allows for reducing the required amount of fresh steam, thereby reducing the overall costs. Vapor recompression is preferably achieved by one or more rotary compressors. Because of the moderate compression stroke of the vapor recompression and thus the limited temperature raise at the heating section falling film evaporators are preferably used, as they can be operated at a small temperature gradient. The falling film evaporator allows for a high evapo- ration rate at small circulation rates and low pressure drops. Thus, falling film evaporators allow for short residence times of the temperature sensible 2'-FL. Moreover, the low pressure drop of falling film evaporators is beneficial for vapor recompression and thus for heat recovery. It is beneficial to connect several evaporators in series, because this allows for keeping the temper- ature difference between heating side and process side high, thereby allowing for small surfac- es in the heat exchanger.

The amount of water removed is usually chosen such that at least at the beginning of the crys- tallization, in particular throughout the crystallization, the concentration of dissolved 2’-FL in the aqueous medium present in the crystallization is in the range as given above and thus may vary from 500 to 750 g/L and in particular from 510 to 720 g/L, depending on the temperature during crystallization. As explained above, a concentration of dissolved 2’-FL of above 630 g/L, in par ticular above 650 g/L in the aqueous medium present during crystallization will lead to the for mation of the crystalline form II having the specified anomeric ratio. It is also apparent that in a continuously operated crystallization the concentration of dissolved 2’-FL in the water present during crystallization is in the ranges given here throughout the crystallization.

For effecting crystallization, the controlled supersaturation is typically induced at a temperature of at least 0°C.

If controlled supersaturation is induced by a process which includes evaporation of water, here- inafter referred to as evaporation crystallization, the temperature where supersaturation is in- duced is typically at least 20°C, in particular at least 25°C, especially at least 30°C or at least 35°C. Generally, the temperature will not exceed 105°C, in particular not exceed 100°C more particularly not exceed 95°C or 90°C, especially not exceed 85°C. In particular the supersatura- tion is induced at a temperature in the range from 0 to 95°C, more particularly in the range from 0 to 90°C especially in the range from 0 to 85°C. If controlled supersaturation is induced by evaporation crystallization, the supersaturation is preferably induced at a temperature in the range from 25 to 95°C, more preferably in the range from 30 to 90°C and especially in the range from 35 to 85°C.

For production of the desired crystalline form II having the specified anomeric ratio, supersatu- ration is typically induced at a temperature in the range from above 60 to 105°C, in particular in the range from 62 to 100°C, especially in the range from 63 to 95°C or from 63 to 90°C or from 63 to 85°C.

If controlled supersaturation is induced by a process which does not include evaporation of wa- ter, e. g. where the temperature where supersaturation is induced by cooling, the temperature may be lower than the above given ranges and may be as low as 0°C. In this case the tempera- ture, where crystallization is induced, is typically in the range from above 60 to 90°C, in particu- lar in the range from above 60 to 80°C, or in the range from above 60 to 70°C.

The crystallization of 2’-FL is usually performed at ambient pressure or under reduced pressure, e.g. at a pressure in the range from 10 to 1020 mbar. The pressure will of course depend on the temperature and the concentration of the aqueous solution of the 2’-FL raw material. It may be beneficial to perform the crystallization of 2’-FL at reduced pressure in order to facilitate removal of water by evaporation during crystallization. Then, crystallization of 2’-FL is preferably per- formed at a pressure in the range from 10 to 900 mbar, in particular from 20 to 800 mbar and especially from 30 to 700 mbar.

During crystallization the temperature may be further reduced and/or water may be further evaporated in order to drive crystallization to completion, in particular, if crystallization is per- formed batch-wise or in semi-batch procedures. Of course, the temperature will be in the above ranges, if crystallization of 2-FL’ is performed continuously.

In order to achieve a control of supersaturation, measures are taken which favor crystallization and prevent kinetic inhibition of crystallization and thus excess oversaturation. Such measures are in particular performing the crystallization in the presence of crystalline 2’-FL.

According to one embodiment of the invention, seed crystals of 2’-FL are added, preferably but not necessarily seed crystals of the desired polymorph form. This measure is in particular taken, if the crystallization is conducted in a discontinuous manner. Then the amount of seed crystals will usually be in the range from 0.01 to 5 % by weight, in particular in the range from 0.02 to 1 % by weight, with respect to pure 2’-FL in the aqueous solution subjected to crystallization in step b).

Surprisingly, even the addition of another polymorph than the polymorph II leads to the for- mation of the desired form II, when the conditions of the crystallization are followed as outlined herein.

In order to perform the crystallization in the presence of crystalline 2’-FL, it is preferred to feed the aqueous solution to a suspension of crystalline 2’-FL in water under conditions of controlled supersaturation. In the aqueous suspension, the solid content is preferably in the range from 5 to 60% by weight, in particular from 10 to 45% by weight and especially from 20 to 40% by weight, based on the total weight of the suspension. Preferably, the concentration of dissolved 2’-FL in the aqueous phase of the suspension of 2’-FL under the conditions of supersaturation is preferably in the ranges specified herein before, and depending on the temperature during crys- tallization.

The crystallization of 2’-FL can be performed in any type of crystallization apparatus which can be utilized for a crystallization of an organic compound from an aqueous solution. Suitable crys- tallization apparatus include but are not limited to stirred tank crystallizers, stirred tank crystal- lizers with guiding pipe, stirred tank crystallizers with guiding pipe and optionally with means for classification of the crystals, so called draft tube crystallizers or draft tube baffle (DIB) crystal- lizers, forced circulation crystallizers optionally having means for crystal classification, such as Oslo-type crystallizers, induced forced circulation crystallizers optionally having means for crys- tal classification, and cooling-plate crystallizers. Preferred crystallizers are selected from the group of forced circulation crystallizers, draft tube crystallizers, draft tube baffled crystallizers, Oslo-type crystallizers and induced forced circulation crystallizers, with particular preference given to draft tube baffled crystallizers and induced forced circulation crystallizers.

As pointed out above, the process of the invention can be performed discontinuously, i.e. bath- wise, or as a semi-batch or continuously.

Batch-wise means that the aqueous solution of the 2’-FL raw material is charged to a crystalli zation vessel and conditions of controlled supersaturation are induced therein in order to effect crystallization of 2’-FL. Thereby 2’-FL is depleted from the solution and thus the concentration of 2’-FL decreases. In order to prevent kinetic inhibition of crystallization, seed crystals of 2’-FL are preferably added. In order to maintain conditions of controlled supersaturation, water may be evaporated during crystallization or the temperature may be decreased during crystallization or both measures are taken.

Semi-batch means that a portion of the aqueous solution of the 2’-FL raw material is charged to a crystallization vessel and conditions of controlled supersaturation are induced therein in order to effect crystallization of 2’-FL. In order to prevent kinetic inhibition of crystallization, seed crys- tals of 2’-FL are preferably added. Then, further amounts of the aqueous solution of the 2’-FL raw material are fed to the crystallization apparatus and thus to the aqueous suspension of par- tially or completely crystallized 2’-FL. In order to maintain conditions of controlled supersatura- tion, water may be evaporated during crystallization or the temperature may be decreased dur- ing crystallization or both measures are taken. Preferably, the crystallization is performed continuously. For this, the aqueous solution of 2’-FL containing raw material provided in step a) is fed to a continuously operated crystallization ap- paratus, which contains an aqueous suspension of 2’-fucosyllactose crystals. In other words, the aqueous solution of 2’-FL is continuously fed to a continuously operated crystallization ap- paratus and the crystallized 2’-FL is continuously discharged from the crystallization apparatus. In the continuously operated crystallization apparatus, conditions of controlled supersaturation are maintained throughout the crystallization. Preferably, conditions of controlled supersatura- tion are maintained by continuously removing defined amounts of water, preferably by evapora- tion, or by cooling or by combinations of these measures.

Frequently, the continuously operated crystallization apparatus is operated in such a manner that the conditions of controlled supersaturation are quasi-statical or almost quasi-statical. In particular, temperature variations are less than 5 K and/or pressure variations are less than 60 mbar.

Generally, the continuously operated crystallization apparatus contains an aqueous suspension of 2’-FL crystals. Preferably, the solids content of the aqueous suspension contained in the con- tinuously operated crystallization apparatus, i.e. the amount of crystalline 2’-FL, is in the range from 5 to 60% by weight, in particular from 10 to 45% by weight, especially from 20 to 40% by weight, based on the total weight of the suspension contained in the continuously operated crystallization apparatus or in the active volume of the continuously operated crystallization ap- paratus. The active volume is understood as those parts of the crystallization apparatus, where the crystallization occurs, e.g. those parts which contain the free flowing aqueous suspension of 2’-FL crystals.

Frequently, step b) of the continuously operated crystallization apparatus comprises the follow- ing sub-steps:

b1) continuously feeding the aqueous solution of 2’-FL raw material to a continuously operat- ed crystallization apparatus containing an aqueous suspension of crystalline 2’-FL, which preferably contains crystalline 2’-FL in an amount from 5 to 60% by weight, in particular from 10 to 45%, especially 20 to 40 % by weight, based on the weight of the suspension; b2) continuously removing water from the aqueous suspension of 2'-FL contained in the crys- tallization apparatus, preferably by evaporation, in particular by evaporation under re- duced pressure;

b3) continuously removing the aqueous suspension of 2'-FL from the crystallization apparatus.

It has been found beneficial if the stream of the aqueous suspension of 2’-FL removed from the crystallizer in step b3) is split into two streams: A first stream is subjected to an isolation of crys- talline 2’-FL, while the remainder is partly fed back to the crystallization apparatus together with fresh aqueous solution of 2’-FL raw material, provided in step b1). For this, a portion of the aqueous suspension of 2’-FL removed in step b3) is mixed with the aqueous solution of 2’-FL raw material of step b1 ) before it is fed to the crystallization apparatus. The thus obtained mix- ture is then fed back it into the crystallization apparatus. The volume ratio of the total stream removed from the crystallizer in step b3) to the first stream is subjected to an isolation of crystal- line 2’-FL is at least 4 : 1 , in particular at least 7 : 1 , more particularly at least 10 : 1 , e.g. from 4 : 1 to 200 : 1 , or from 7 : 1 to 80 : 1 or from 10 : 1 to 60 : 1.

In order to remove water by evaporation the energy necessary for evaporation must be intro- duced into the crystallizer. This may be achieved by conventional heating elements. Preferably the evaporation heat is introduced into the crystallizer by feeding a heated stream of the aque- ous solution of the 2'-FL raw material to the reactor. The heated stream of the aqueous solution of 2’-FL raw material which is fed into the reactor may be heated by any conventional heat ex- changer. The heat exchanger may be operated with conventional heating media such as heat- ing oils or heating steam, including steam from a steam network or steam provided in the pro- cess of the present invention by vapor recompression of water evaporated during crystallization or concentration of the aqueous solution of 2'-FL raw material. Preferably, the heated solution of 2’-FL raw material, which is fed into the crystallizer, is heated by using a forced circulation de- compression evaporator, which is preferably heated by steam from vapor recompression of the water evaporated during crystallization or concentration of the aqueous solution of the 2'-FL raw material. Using a forced circulation decompression evaporator minimizes fouling on the heat exchanger surfaces.

The continuously operated crystallization apparatus is preferably a forced circulation crystallizer. In step c) the crystallized 2’-FL is separated from the aqueous mother liquor. For this, the sus- pension of crystallized 2’-FL in the aqueous mother liquor is subjected to solid/liquid separation. Suitable measures for the separation of solids from liquids include centrifugation, filtration, or washing towers. Means for centrifugation may include, but are not limited to, pusher centrifuges, worm screen centrifuges, peeler centrifuges and decanters. Means for filtration may include, but are not limited to, rotary pressure filters, belt filters, suction filters, chamber filters and chamber filter presses. Suitable washing towers may include, but are not limited to, gravity wash col- umns, mechanical wash columns, hydraulic wash columns and piston type wash columns. Pref- erably, solid/liquid separation is performed by centrifugation, in particular by utilizing a pusher centrifuge or a worm screen centrifuge, because thereby low residual moisture in the obtained solid can be achieved, which is frequently less than 10% by weight, e.g. from 1 to 8% by weight.

The solid/liquid separation may be performed stepwise or is preferably performed continuously. The obtained solid may be washed in order to remove adherent mother liquor, e.g. by cold sol- vent such as water or a saturated aqueous solution of pure 2’-FL. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mixture of water and a non-solvent for 2’- FL. Typical non-solvents are C1-C4-alkanols, such as methanol, ethanol, n-propanol or n- butanol, and acetic acid. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mother liquor of a subsequent crystallization step, if the crystallization is per- formed in more than one crystallization stages. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mixture of water and a non-solvent for 2’-FL, i.e. a mixture of non-solvent and mother liquor of a subsequent crystallization step, if the crystallization is per formed in more than one crystallization stages. Washing may be performed e.g. by spraying the solid crystalline 2'-FL with the cold solvent followed by a further liquid/solid separation or by suspending solid crystalline 2'-FL in the cold solvent followed by a further liquid/solid separation. The washing may be performed in a single step or by multiple washing steps, e.g. by 2, 3 or more steps. If the washing is performed by multiple washing steps, the washing steps may be operated concurrently or preferably countercurrently.

The crystallization of 2'-FL will frequently comprise a single crystallization step, as a single crys- tallization will generally ensure a purity of 2’-FL, which is sufficient for most purposes. However, the crystallization of 2'-FL may comprise two or more crystallization steps, 2 or 3 subsequent crystallization steps or stages. Thereby, more compact crystals of 2'-FL are obtained, which have a low aspect ratio. Moreover, the crystalline 2'-FL obtained in a second or third crystalliza- tion step may have a larger particle size and/or higher purity. Further crystallization stages per formed in accordance with the method described above involving crystallization under condi- tions of controlled supersaturation may be useful to further increase the purity of the desired 2’- FL.

In a multi-stage crystallization method, the aqueous solution of the 2'-FL raw material provided in step a) is fed to a crystallization stage (1), which is operated batch-wise or preferably operat- ed continuously as described above. The crystalline 2'-FL obtained in this stage (1 ) is then dis- solved in water and the obtained solution is subjected to a subsequent crystallization step (2), where a purified crystalline 2'-FL and a further mother liquor is obtained. Preferably, the mother liquor of the subsequent crystallization step (2) is mixed with water and the mixture is used for dissolving the crystalline 2'-FL obtained in crystallization step (1). The crystalline 2'-FL obtained in stage (2) may be subjected to one or more, e.g. to 1 or 2 further crystallization stages (3) and (4), respectively. Preferably, the mother liquor of the subsequent crystallization step (n+1) is mixed with water and this mixture is used for dissolving the crystalline 2'-FL obtained in crystal- lization step (n), where n indicates the respective crystallization step. The mother liquor of the first crystallization stage may be discarded or subjected to a further crystallization stage to ob- tain a residual liquor, which is discarded, and crystalline 2'-FL of lower purity. The crystalline 2'- FL of lower purity obtained in said crystallization stage may be dissolved, e.g. in the aqueous solution of 2'-FL provided in step a) to obtain a more concentrated solution, which is fed into the crystallization step (1 ). The crystalline 2'-FL obtained in said crystallization from the mother liq uor of step (1) may also be dissolved in a mixture of water and the mother liquor obtained in crystallization step (1) and combined with the aqueous solution of 2'-FL provided in step a) to obtain a more concentrated solution, which is fed into the crystallization step (1).

According to the invention, at least crystallization stage (1) is performed in accordance with the method described above, which involves crystallization under conditions of controlled supersat- u rati on. If the crystallization stage is followed by the crystallization stage (2), also crystallization stage (2) is preferably performed in accordance with the method described above, which in- volves crystallization under conditions of controlled supersaturation.

Embodiment 10: Process according to any of embodiments 7 to 9 wherein the process encom- passes the further step of exposing the crystals to vapor of water under conditions suitable to further reduce the content of residual organic residues such as organic solvents.

It is known from WO 2018/077368 A1 to reduce quantity or concentration of a residue of an or ganic solvent in or on a crystalline oligosaccharide hydrate, comprising exposing the crystalline oligosaccharide hydrate to water vapor.

This process step as disclosed in WO 2018/077368 A1 may be of course implemented as a process step, to be inserted in the process of the present invention at various points: it may be inserted after the obtaining of the crystalline material, preferably after the washing of the crys- tals, and or after the drying of the obtained crystals. In case an organic solvent is employed for the washing, the step of exposing the crystalline 2’-FL to water vapor is preferably inserted after an initial drying step, if the amount of organic solvent employed is relatively high, i.e. about 10 percent or more of the solvent mixture employed for the washing, as in this case it may be de- sirable to remove the larger part of the organic solvent by conventional drying means and then use the step of exposing to water vapor to reduce the residual content of organic solvent within the obtained 2’-FL. In case the amount of employing organic solvent amounting to less than 10 percent of the solvent mixture employed for the washing, then the step of exposing to water vapor to reduce the residual content of organic solvent within the obtained 2’-FL may be suc- cessfully employed directly; in the latter case, it may be desirably to increase the contact time to enable an as low reduction as in the first case, as in the latter case the amount of organics sol- vent being present within the wet crystals may be considerably higher than in the first case when the wet crystals are subjected to this step.

In a preferred embodiment, the process of the present invention, specifically embodiment 10, encompasses the described step of exposing the crystalline 2’-FL to water vapor, such step preferably being inserted into the process directly after obtaining the wet crystals of 2’-FL of form II having the specified anomeric ratio.

Embodiment 1 1 : Crystalline form of any of the embodiments 1 to 6 obtained by the process of any of the embodiments 7 to 10.

Embodiment 12: Crystalline form II of 2'-0-Fucosyllactose having an alpha:beta anomeric ratio of from 40:60 to 60:40, preferably from 45:55 to 55:45, more preferably from 40:52 to 52:48, even more preferably from about 50:50 such as exactly 50:50, with a purity of 2’-FL of at least 98, preferably at least 99, even more preferably at least 99.5 percent by weight based on total saccharides, and a 2’-FL-content of at least 90 percent, preferably at least 92, more preferably at least 94, even more preferably at least 95, and most preferably at least 96 percent by weight based on total solids such as 97, 98 or even 99 or more and every value in between, and/or a residual solvent content of organic solvents of at most 0.5, preferably at most 0.1 , more pre- ferred at most 0.05, even more preferred at most 0.01 percent by weight based on total solid. The process of the invention as described herein reliably yields the crystalline form II of 2'-0- Fu cosy I lactose having the specified alpha:beta anomeric ratio as defined in embodiments 1 1 and 12.

Embodiment 13: Nutritional formulation, specifically infant formula, or pharmaceutical formula- tion, comprising the crystalline form of any of the embodiments 1 to 6 or 11 or 12 or obtained from the process according to embodiment 7 to 10.

It is well-known in the art that the primary use of the HMO-molecule 2’-FL is the supplementa- tion of infant nutrition products (so-called infant formulas) to bring those formulas - which are usually based on bovine milk which does not contain 2’-FL - closer to the human breast milk. Besides that use, other uses for human adults and human children and babies (i.e. not being infants) are also known from literature.

Embodiment 14: Use of crystalline form according to any of the embodiments 1 to 6 or 1 1 or 12 or obtained from the process according to any of the embodiments 7 to 10 for the preparation of

A) a nutritional formulation

a. to booster the development and/or improvement of the brain, the immune system, intestine microbiotic environment of an infant or baby; and/or

b. the improvement and/or maintenance of the brain, the immune system, intestine mi- crobiotic environment, general physical ability and/or the resistency against patho- genic attacks within a human child or adult, or

B) a cosmetic formulation for the maintenance and/or improvement of the skin such as elas- ticity, resistency against pathogenic attacks and/or the microbiota of the skin; or

C) a pharmaceutical formulation for the treatment and/or prevention of diseases or disorders of the brain, the immune system, the microbiotic environment of the skin and/or the intes- tines, the general physical ability; and/or of pathogenic attacks within humans or animals.

As it is known so far, 2’-FL has many uses; all of them can of course be accessed with the crys- talline form II of 2'-0-Fucosyllactose having the specified alpha:beta anomeric ratio as defined in the embodiments of the present invention. For example, it is known to use breast milk of lac- tating mothers to treat skin disorders of the infant but also of the mother, such as reddening of the skin of the infant or of the breast of the nurturing mother etc. Within the scientific community, it is currently at least assumed if not yet proven that the HMO in breast milk, with 2’-FL being one of the most abundant ones therein, at least attributing to such effect.

A specific advantage of the crystalline form II of 2'-0-Fucosyllactose having the specified al- pha:beta anomeric ratio as defined in the embodiments of the present invention is its improved stability - among other improved properties - over other polymorphs know up to date. Hence, nutritional, skin care and pharmaceutical formulations encompassing the crystalline form II of 2'- O-Fucosyllactose having the specified alpha:beta anomeric ratio as defined in the embodiments herein can make use of that improved properties to yield formulations having better handling properties and/or better stability, as the herein claimed crystalline form II of 2’-FL is in a very stable form, presumably in the most stable form 2’-FL can exhibit as a crystalline material. Hence, no further change in crystal modification is expected to take place into any other poly- morph, either known or possibly unknown. This is of great advantage, as regulatory regulations in the area of infant nutrition but also for pharmaceuticals require a constant delivery of the very same polymorph of the active ingredient (the“active ingredient” being here 2’-FL). Thus, with the provision of the very stable and presumably most stable polymorph - the crystalline form II of 2'-0-Fucosyllactose having the specified alpha:beta anomeric ratio as defined in the embod- iments herein - enables the users to produce and supply reliably the formulations comprising 2’- FL in the form of the polymorph of this present invention.

Embodiment 15: Formulation according to embodiment 13 having an improved storage stability when compared to formulations comprising other crystalline forms of 2'-0-Fucosyllactose than the crystalline form of any of the embodiments 1 to 6 or 1 1 or 12 or obtained from the process according to any of the embodiments 7 to 10.

An major advantage is the improved storage stability, as - as outlined before - the crystalline form II of 2'-0-Fucosyllactose having the specified alpha:beta anomeric ratio as defined in the embodiments of the present invention is already in a very stable, presumably in its most stable form. Thus, obviously, no further change in crystal structure is to be expected upon storage, tempering etc. As a result, no change in morphology and thus in its macroscopic properties is to be expected, yielding to a stable environment around the 2’-FL-crystals and thus, in its final consequence, in an unchanged environment within formulations, such as those defined herein as the previous embodiments 13 and 15 and those of embodiment 14 for which the crystalline 2’-FL of this invention can be used.

Embodiment 16: Nutritional preparation comprising the formulation according to embodiment 13 or 15, comprising water and optional at least one further suitable ingredient selected from lac- tose, mono-, di- and/or oligosaccharides (other than 2’-FL), vitamins, minerals, pre-biotics, pro- biotics, wherein the ratio of alpha:beta anomers of 2'-0-Fucosyllactose remains stable, wherein the preparation is not mammalian milk.

Embodiment 17: Nutritional preparation according to embodiment 16, wherein the a^-anomeric ratio is about 50:50, preferably 50:50.

Embodiments 16 and 17 described nutritional preparations comprising the crystalline form II of 2'-0-fucosyllactose having the specified alpha:beta anomeric ratio as defined in the previous embodiments of the present invention, further containing typical ingredients which are employed within the various nutritional formulations known to the person of skill in the art of nutrition.

Embodiment 18: Method of treating a nutritional preparation according to embodiment 16 or 17, wherein the preparation is kept at elevated temperature of at least 30°C, preferably at least 35°C, for a period of at least 3, preferably 5, more preferably at least 7 minutes.

Embodiment 18 further enhances the stability of the crystalline form II of 2'-0-fucosyllactose having the specified alpha:beta anomeric ratio as defined in the previous embodiments of the present invention by further promoting or enhancing the anomeric ratio of the crystalline form II of 2'-0-fucosyl lactose having the specified alpha:beta anomeric ratio as defined in the previous embodiments of the present invention.

This may be of help to further similiarize the 2’-FL from synthetic origin towards the 2’-FL occur ring in breast milk, as the 2’-FL in breast milk is suspected to be in an anomeric ratio of about 50:50 as in the case of the 2’-FL of the present invention.

Not wishing being bound by the following theory, rational for this expectation of a higher“simi- larity with 2’-FL within breast milk” is the observation made in this present invention that the crystalline form II of 2'-0-fucosyllactose having the specified alpha:beta anomeric ratio as de- fined in the previous embodiments of the present invention exhibits an excellent stability, and thus - also in view of the“storage conditions” of breast milk - it seems likely that 2’-FL in the breast milk might have the same anomeric ratio.

Thus, the present invention provides a 2’-FL in crystalline form having an anomeric ratio which likely is the same or very close to the ratio of natural occurring 2’-FL in the breast milk. As a result, the present invention enables the use of such synthetic 2’-FL in basically the same form as the natural 2’-FL for commercial use in nutritional and pharmaceutical and skin care formula- tions.

Improved properties of the presently claimed crystalline 2’-FL of the embodiments of the inven- tion are: better filterability, better drying properties, lower hygroscopicity, better milling proper- ties, higher compatibility with lactose, starch or linoleic acid, olinolenic acid and the like, higher physical stability as dry (amorphous) powder.

The present invention is further illustrated by the following set of embodiments and combina- tions of embodiments resulting from the dependencies and back-references as indicated hereinunder. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The chemical composition of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as be- ing synonymous to "The chemical composition of any one of embodiments 1 , 2, 3, and 4". Fur- ther, it is explicitly noted that the following set of embodiments is not the set of claims determin- ing the extent of protection, but represents a suitably structured part of the description directed to general and preferred aspects of the present invention.

1 '. A solid chemical composition, wherein from 90 to 100 weight- % of said composition con- sist of crystalline form II of 2'-0-fucosyl lactose of formula (I)

wherein said crystalline form exhibits an a:b anomeric ratio in the range of from 40:60 to 60:40 determined by ¹³ C-NMR, wherein said composition has an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Koi,2 radiation having a wavelength of 0.15419 nm.

2'. The chemical composition of embodiment T, wherein from 91 to 100 weight-%, preferably from 92 to 100 weight-%, more preferably from 93 to 100 weight-%, more preferably from 94 to 100 weight-%, more preferably from 95 to 100 weight-%, more preferably from 96 to 100 weight-% of said composition consist of said crystalline form.

3'. The chemical composition of embodiments 1 ' or 2', wherein from 97 to 100 weight-% or from 98 to 100 weight-% or from 99 to 100 weight-% of said composition consist of said crystalline form.

4'. The chemical composition of any one of embodiments T to 3', wherein the X-ray powder diffraction pattern further comprises one or more reflections, preferably two or more reflec- tions, more preferably three or more reflections, more preferably four or more reflections, more preferably five or more reflections, more preferably six reflections at 2Q angles (1.70 ± 0.20)°, (11.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°.

5'. The chemical composition of any one of embodiments T to 4', wherein the a:b anomeric ratio is in the range of from 45:55 to 55:45, preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49.

6'. The chemical composition of any one of embodiments T to 5', wherein the a:b anomeric ratio is 50:50.

7'. The chemical composition of any one of embodiments T to 6', having a total content of saccharides other than 2'-0-fucosyl lactose in the range of from 0 to 4 weight-%, prefera- bly in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, based on the total weight of all saccharides comprised in said composition. '. The chemical composition of embodiment 7', wherein the saccharides other than 2'-0- fucosyl lactose are at least one monosaccharide or at least one oligosaccharide other than 2'-0-fucosyl lactose or a mixture of at least one monosaccharide and at least one oli- gosaccharide other than 2'-0-fucosyl lactose. '. The chemical composition of embodiment 7' or 8', wherein the at least one saccharide other than 2'-0-fucosyl lactose comprises, more preferably is, one or more of lactose, fu- cosylated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and op- tionally one or more further oligosaccharides other than those mentioned before, more preferably comprises, more preferably is, one or more of lactose, fucosylated lactose, fu- cose, galactose, glucose, lactulose and fucosylated lactulose, wherein the fucosylated lac- tose preferably comprises, more preferably is, difucosyl lactose, and wherein the difucosyl lactose preferably comprises, more preferably is, one or more of 2’,2”-0-difucosyl lactose and 2’,3-O-difucosyl lactose. 0'. The chemical composition of any one embodiments 1 ' to 9', having a total content of or ganic compounds other than 2'-0-fucosyl lactose in the range of from 0 to 9 weight-%, preferably in the range of from 0 to 8 weight-%, more preferably in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 3 weight-%, more preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, based on the total weight of all organic compounds comprised in said composition. 1 '. The chemical composition of any one embodiments T to 10', having a total content of or ganic solvents in the range of from 0 to 3 weight-%, preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.01 weight-%, based on the total weight of said composition. 2'. The chemical composition of embodiment 1 1', wherein the organic solvents have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar(abs), the or ganic solvents preferably being one or more of one or more organic alcohols, one or more alkanoic acids, and a mixture of one or more organic alcohols, one or more alkanoic ac- ids, wherein the one or more organic alcohols are preferably one or more of C1 , C2, C3 and C4 alcohols and wherein the one or more one or more alkanoic acids are preferably one or more of C1 , C2, C3 and C4 alkanoic acids. 3'. The chemical composition of any one of embodiments T to 12', having a water content in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, based on the total weight of said composition, determined by Karl Fischer titration.

14'. The chemical composition of any one of embodiments T to 13', being in the form of crys- tals having a ratio lengthdhickness of at most 10:1 , preferably of at most 5:1 , more prefer- ably of at most 2:1.

15'. The chemical composition of embodiment 14', wherein the ratio lengtfcthickness is in the range of from 1 :1 to 10:1 , preferably in the range of from 1.1 :1 to 5:1 , more preferably in the range of from 1.2:1 to 2:1.

16'. The chemical composition of any one of embodiments T to 15', being in the form of crys- tals having an average particle size in the range of from 0.2 to 1.5 mm, preferably in the range of from 0.3 to 1.0 mm, wherein the average particle size is the weight average par- ticle size.

17'. The chemical composition of embodiment 16', wherein from 0 to 10 weight-% of the parti- cles have a size of less than 100 micrometer.

1 . Crystalline form II of 2'-0-fucosyl lactose of formula (I)

having an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Ka-i,2 radiation having a wavelength of 0.15419 nm, said crystalline form exhibiting an a:b anomeric ratio in the range of from 40:60 to 60:40, determined by ¹³ C-NMR.

2. The crystalline form of embodiment 1 , wherein the X-ray powder diffraction pattern further comprises one or more reflections, preferably two or more reflections, more preferably three or more reflections, more preferably four or more reflections, more preferably five or more reflections, more preferably six reflections at 2Q angles (1.70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°.

3. The crystalline form of embodiment 1 or 2, wherein the a:b anomeric ratio is in the range of from 45:55 to 55:45, preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49. The crystalline form of any one of embodiments 1 to 3, wherein the a:b anomeric ratio is 50:50. The crystalline form of any one of embodiments 1 to 4, having a purity with regard to said crystalline form in the range of from 90 to 100 weight-%, preferably in the range of from 91 to 100 weight-%, more preferably in the range of from 92 to 100 weight-%, more prefera- bly in the range of from 93 to 100 weight-%, more preferably in the range of from 94 to 100 weight-%, more preferably in the range of from 95 to 100 weight-%, more preferably from 96 to 100 weight-%. The crystalline form of embodiment 5, having a purity with regard to said crystalline form in the range of from 97 to 100 weight-% or in the range of from 98 to 100 weight-% or in the range of from 99 to 100 weight-%. The crystalline form of any one of embodiments 1 to 6, having a total content of saccha- rides other than 2'-0-fucosyl lactose in the range of from 0 to 4 weight-%, preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, based on the total weight of all saccha- rides comprised in said crystalline form. The crystalline form of embodiment 7, wherein the saccharides other than 2'-0-fucosyl lactose are at least one monosaccharide or at least one oligosaccharide other than 2'-0- fucosyl lactose or a mixture of at least one monosaccharide and at least one oligosaccha- ride other than 2'-0-fucosyl lactose. The crystalline form of embodiment 7 or 8, wherein the at least one saccharide other than 2'-0-fucosyl lactose comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and optionally one or more further oligosaccharides other than those mentioned before, more preferably corn- prises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose and fucosylated lactulose, wherein the fucosylated lactose preferably comprises, more preferably is, difucosyl lactose, and wherein the difucosyl lactose prefer- ably comprises, more preferably is, one or more of 2’,2”-0-difucosyl lactose and 2’, 3-0- difucosyl lactose. The crystalline form of any one embodiments 1 to 9, having a total content of organic compounds other than 2'-0-fucosyl lactose in the range of from 0 to 9 weight-%, prefera- bly in the range of from 0 to 8 weight-%, more preferably in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 3 weig t-%, more preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, based on the total weight of all organic compounds comprised in said crystalline form.

1 1. The crystalline form of any one embodiments 1 to 10, having a having a total content of organic solvents in the range of from 0 to 3 weight-%, preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.01 weight-%, based on the total weight of said crystalline form.

12. The crystalline form of embodiment 11 , wherein the organic solvents have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar(abs), the organic solvents preferably being one or more of one or more organic alcohols, one or more alka- noic acids, and a mixture of one or more organic alcohols, one or more alkanoic acids, wherein the one or more organic alcohols are preferably one or more of C1 , C2, C3 and C4 alcohols and wherein the one or more one or more alkanoic acids are preferably one or more of C1 , C2, C3 and C4 alkanoic acids.

13. The crystalline form of any one of embodiments 1 to 12, having a total water content in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, based on the total weight of said composition, determined by Karl Fischer titra- tion.

14. The crystalline form of any one of embodiments 1 to 13, being in the form of crystals hav- ing a ratio length:thickness of at most 10:1 , preferably of at most 5:1 , more preferably of at most 2:1.

15. The crystalline form of embodiment 14, wherein the ratio length dhickness is in the range of from 1 :1 to 10:1 , preferably in the range of from 1.1 :1 to 5:1 , more preferably in the range of from 1.2:1 to 2:1.

16. The crystalline form of any one of embodiments 1 to 15, being in the form of crystals hav- ing an average particle size in the range of from 0.2 to 1.5 mm, preferably in the range of from 0.3 to 1.0 mm, wherein the average particle size is the weight average particle size.

17. The crystalline form of embodiment 16, wherein from 0 to 10 weight-% of the particles have a size of less than 100 micrometer.

18. A process for preparing crystalline form II of 2'-0-fucosyl lactose (2’-FL) of formula (I) having an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Ka-i _,2 radiation having a wavelength of 0.15419 nm, preferably a process for preparing crystalline form II of 2'-0-fucosyl lactose according to any one of embodiments 1 to 17 and/or for preparing a composition according to any one of embodiments T to 17', said process comprising

(a) providing an aqueous mixture comprising a saccharide composition dissolved in wa- ter, wherein from 70 to 100 weight- % of the saccharide composition consist of 2'-0- fucosyl lactose; and

adjusting the temperature of the provided mixture to a value in the range of from 20 to 95 °C at ambient pressure and maintaining the temperature of the mixture at a value in this range until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio in the range of from 40:60 to 60:40, determined by ¹³ C-NMR;

(b) subjecting the mixture obtained from (a) to crystallization conditions, obtaining a crystallization mixture comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor;

(c) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b). The process of embodiment 18, wherein in the mixture provided in (a), the concentration of the 2'-0-fucosyl lactose is in the range of from 200 to 750 g/L, preferably in the range of from 250 to 650 g/L, more preferably in the range of from 300 to 600 g/L, more preferably in the range of from 350 to 550 g/L, more preferably in the range of from 400 to 500 g/L. The process of embodiment 18 or 19, wherein the saccharide composition according to (a) additionally comprises at least one saccharide other than 2'-0-fucosyl lactose, prefer- ably at least one monosaccharide or at least one oligosaccharide other than 2'-0-fucosyl lactose or a mixture of at least one monosaccharide and at least one oligosaccharide oth- er than 2'-0-fucosyl lactose. The process of embodiment 20, wherein from 70 to 99.5 weight-%, preferably from 75 to 95 weight-%, more preferably from 78 to 92 weight-% of the saccharide composition ac- cording to (a) consist of 2'-0-fucosyl lactose, based on the total amount of all saccharides comprised in the saccharide composition, preferably all monosaccharides and oligosac- charides comprised in the saccharide composition. 22. The process of embodiment 21 , wherein from 30 to 0.5 weight-%, preferably from 25 to 5 weight-%, more preferably from 22 to 8 weight-% of the saccharide composition according to (a) consist of the at least one saccharide other than 2'-0-fucosyl lactose, preferably consist of the at least monosaccharide or the at least one oligosaccharide other than 2 0 fucosyl lactose or the mixture of at least one monosaccharide and at least one oligosac- charide other than 2'-0-fucosyl lactose.

23. The process of embodiment 22, wherein the at least one saccharide other than 2'-0- fucosyl lactose comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and optionally one or more further oligosaccharides other than those mentioned before, more preferably comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glu cose, lactulose and fucosylated lactulose.

24. The process of embodiment 23, wherein the at least one saccharide other than 2 0

fucosyl lactose comprises fucosylated lactose, preferably difocusyl lactose.

25. The process of embodiment 23 or 24, wherein the fucosylated lactose comprises difucosyl lactose, wherein the difucosyl lactose preferably comprises one or more of 2’,2”-0- difucosyl lactose and 2’,3-O-difucosyl lactose.

26. The process of embodiment 24 or 25, wherein the saccharide composition according to (a) comprises the fucosylated lactose in an amount in the range of from 0.5 to 10, prefer ably in the range of from 0.5 to 8 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 0.5 to 4 weight-%, based on the total amount of all saccharides comprised in the saccharide composition, preferably all mono- saccharides and oligosaccharides comprised in the saccharide composition.

27. The process of embodiment 24 or 25, wherein the at least one saccharide other than 2'-0- fucosyl lactose comprises lactulose, or fucosylated lactulose, or a mixture of lactulose and fucosylated lactulose.

28. The process of embodiment 27, wherein the saccharide composition according to (a) comprises said comprises said lactulose, or said fucosylated lactulose, or said mixture of lactulose and fucosylated lactulose in an amount in the range of from 0.5 to 10, preferably in the range of from 0.5 to 8 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 0.5 to 4 weight-%, based on the total amount of all saccharides comprised in the saccharide composition, preferably all mono- saccharides and oligosaccharides comprised in the saccharide composition.

29. The process of any one of embodiments 20 to 28, wherein from 98 to 100 weight-%, pref- erably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more prefer- ably from 99.9 to 100 weight- % of the saccharide mixture according to (a) consist of 2'-0- fucosyl lactose and the at least one saccharide other than 2'-0-fucosyl lactose, preferably consist of

2'-0-fucosyl lactose and

the at least one monosaccharide or the at least one oligosaccharide other than 2'-0- fucosyl lactose or a mixture of at least one monosaccharide and at least one oligo saccharide other than 2'-0-fucosyl lactose.

30. The process of any one of embodiments 18 to 29, wherein the mixture provided according to (a) further comprises one or more organic solvents.

31. The process of embodiment 30, wherein the one or more organic solvents have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar, the one or more organic solvents preferably being at least one organic alcohols, or at least one alka- noic acid, or a mixture of at least one organic alcohols and at least one alkanoic acids, wherein the at least one organic alcohol is preferably one or more of C1 , C2, C3 and C4 alcohols and wherein the at least one alkanoic acid is preferably one or more of C1 , C2, C3 and C4 alkanoic acids.

32. The process of embodiment 30 or 31 , wherein in the mixture provided according to (a), the weight ratio of the organic solvents relative to the water is in the range of from 0:1 to 0.05:1 , preferably in the range of from 0:1 to 0.02:1 weight-%, more preferably in the range of from 0:1 to 0.01 :1.

33. The process of any one of embodiments 18 to 32, wherein from 98 to 100 weight-%, pref- erably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more prefer- ably from 99.9 to 100 weight-% of the mixture provided according to (a) consist of the wa- ter, the saccharide composition and optionally the one or more organic solvents according to any one of embodiments 30 to 32.

34. The process of any one of embodiments 18 to 33, wherein the 2'-0-fucosyl lactose corn- prised in the saccharide composition comprised in the mixture provided according to (a) exhibits an a:b anomeric ratio in the range of from 0:100 to 100:0, preferably

in the range of from 0:100 to 35:65, more preferably in the range of from 10:90 to 30:70, more preferably in the range of from 15:85 to 25:75; or

in the range of from 100:0 to 65:35, more preferably in the range of 90:10 to 70:30, more preferably in the range of from 85:15 to 75:25.

35. The process of any one of embodiment 18 to 34, wherein the aqueous mixture comprising the saccharide composition provided according to (a) is obtainable or obtained by a pro- cess comprising a chemical or a biochemical method, preferably a biochemical method. 36. The process of any one of embodiment 18 to 34, wherein providing the aqueous mixture comprising the saccharide composition according to (a) comprises preparing said aque- ous mixture, said preparing comprising a chemical or a biochemical method, preferably a biochemical method.

37. The process of embodiment 35 or 36, wherein the biochemical method comprises enzy- matically biocatalytically fucosylating lactose to obtain 2'-0-fucosyl lactose.

38. The process of any one of embodiments 35 to 37, wherein the biochemical method corn- prises a fermentation process which preferably comprises

(i) preparing a fermentation broth comprising a culture medium and an aqueous super- natant thereof, wherein the supernatant comprises 2'-0-fucosyl lactose at a concen- tration of at least 25 g/L, preferably in the range of from 25 to 150 g/L, more prefera- bly in the range of from 25 to 120 g/L, and wherein the supernatant optionally corn- prises difucosyl lactose, preferably at a concentration in the range of from 1.5 to 20 weight- % based on the amount of 2'-0-fucosyl lactose comprised in the superna- tant;

(ii) separating the supernatant from the culture medium;

(iii) optionally subjecting the supernatant obtained from of (ii) to a post-treatment corn- prising demineralization and/or chromatography.

39. The process of embodiment 38, wherein the demineralization comprises contacting the supernatant with one or more ion exchange resins, preferably comprises contacting the supernatant with at least one cation exchange resin which is preferably in H ⁺ form and wherein preferably at least one, more preferably all of the cation exchange resins, is a strong cation exchange resin, and with at least one anion exchanges resin which is pref- erably in free base form and wherein preferably at least one of the anion exchange resins, preferably all of the anion exchange resins, is a strong exchange resin.

40. The process of embodiment 38 or 39, wherein the demineralization comprises subjecting the supernatant to electrodialysis.

41. The process of any one of embodiments 18 to 40, wherein according to (a), the tempera- ture of the provided mixture is maintained until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio in the range of from 45:55 to 55:45, preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more prefera- bly in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49.

42. The process of embodiment 41 , wherein according to (a), the temperature of the provided mixture is maintained the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ra- tio of 50:50. 43. The process of any one of embodiments 18 to 42, wherein according to (a), the tempera- ture of the provided mixture is adjusted to a value in the range of from 10 to 90 °C, in a first alternative i) preferably in the range of from 30 to 85 °C, more preferably in the range of from 40 to 80 °C, more preferably in the range of from 50 to 75 °C, more preferably in the range of from 60 to 70 °C, at ambient pressure, in a second alternative ii) preferably in the range of from 10 to 60 °C, more preferably in the range of from 10 to 50 °C, more preferably in the range of from 10 to 40 °C, more preferably in the range of from 15 to 30 °C, at ambient pressure.

44. The process of any one of embodiments 18 to 43, preferably according to any one of em bodiments 19, and 20 to 43 insofar as being dependent on embodiment 19, wherein prior to or during (b), the mixture is concentrated to a concentration of the 2'-0-fucosyl lactose of at least 500 g/L, preferably in the range of from 500 to 750 g/L, more preferably in the range of from 510 to 720 g/L, more preferably in the range of from 550 to 720 g/L, more preferably in the range of from 600 to 720 g/L, more preferably in the range of from 630 to 720 g/L, more preferably in the range of from 650 to 720 g/L.

45. The process of embodiment 44, wherein concentrating the mixture comprises separating water from the mixture.

46. The process of embodiment 45, wherein water is separated from the mixture at a pressure of less than 1 bar(abs), more preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more preferably in the range of rom 50 to 800 mbar(abs).

47. The process of embodiment 45 or 46, preferably 46, wherein water is separated from the mixture at a temperature of the mixture of at least 20 °C, preferably in the range of from 20 to 105 °C, more preferably in the range of from 25 to 105 °C, more preferably in the range of from 30 to 105 °C, more preferably in the range of from 35 to 105 °C, more pref erably in the range of from 60 to 105 °C, more preferably in the range of from 60 to 100 °C, more preferably in the range of from 60 to 95 °C.

48. The process of any one of embodiments 18 to 47, wherein the crystallization conditions according to (b) comprise one or more of

supersaturating the mixture;

adding an anti-solvent for 2'-0-fucosyl lactose;

lowering the temperature of the mixture;

stirring the mixture;

adding seed crystals of 2'-0-fucosyl lactose to the mixture;

removing water from the mixture.

49. The process of any one of embodiments 18 to 48, wherein in the crystallization mixture during crystallization according to (b), the supersaturation of the mixture is characterized by a ratio c:c ^* in the mixture in the range of from 1.00001 : 1 to 1.5:1 , wherein c/(g/L) is the concentration of 2'-0-fucosyl lactose dissolved in the water comprised in the crystallization mixture under the given crystallization conditions, and wherein c (g/L) is the equilibrium solubility of 2'-0-fucosyl lactose in water under these conditions. The process of embodiment 49, wherein the ratio c:c ^* is in the range of from 1.00005:1 to 1.4:1 , preferably in the range of from 1.0001 :1 to 1.3:1 , more preferably in the range of from 1.0005:1 to 1.2:1 , more preferably in the range of from 1.001 :1 to 1.2:1 , more prefer- ably in the range of from 1.002:1 to 1.15:1. The process of embodiment 49 or 50, wherein adjusting the supersaturation of the mixture comprises removing water from the mixture. The process of embodiment 51 , wherein removing water from the mixture comprises sub- jecting the mixture to a pressure of less than 1 bar(abs), preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more prefer- ably in the range of from 50 to 800 mbar(abs). The process of embodiment 52,

wherein the water is removed from the mixture at a temperature of the mixture of at least 20 °C, preferably in the range of from 20 to 105 °C, more preferably in the range of from 25 to 105 °C, more preferably in the range of from 30 to 100 °C, more preferably in the range of from 35 to 95 °C; or

wherein the water is removed from the mixture at a temperature of the mixture in the range of from 60 to 105 °C, preferably in the range of from 61 to 100 °C, more preferably in the range of from 62 to 95 °C, more preferably in the range of from 63 to 90 °C, more preferably in the range of from 63 to 85 °C. The process of embodiment 51 , wherein the water is removed from the mixture at a pres- sure of 1 bar(abs) and a temperature of the mixture in the range of from 0 to 90 °C, pref- erably in the range of from 60 to 90 °C, more preferably in the range of from 60 to 80 °C, more preferably in the range of from 60 to 70 °C. The process of any one of embodiments 48 to 54, wherein the anti-solvent for 2'-0-fucosyl lactose is one or more of at least one C1 to C6 alcohol and at least one organic acid, wherein the at least one C1 to C6 alcohol is selected from the group consisting of metha- nol, ethanol, at least one propanol, at least one butanol, and at least one hexanol, and wherein the at least one organic acid is preferably one or more of acetic acid and propion- ic acid. The process of any one of embodiments 48 to 55, wherein the temperature of the mixture is lowered from a value of at least 60 °C to a value of below 60 °C, preferably in the range of from 0 to 55 °C. 57. The process of embodiment 56, wherein the temperature of the mixture is lowered step- wise to a value of below 60 °C, preferably in two or more steps, wherein in a first step, the temperature of the mixture is lowered to a value in the range of from 40 to 55 °C and the temperature is maintained at this value for a period of time, and wherein in a second step, the temperature of the mixture is lowered to a value in the range of from 0 to less than 40 °C, preferably in the range of from 5 to 35 °C, wherein according to said second step, the temperature is optionally lowered in a first sub-step to a value in the range of from 15 to 35 °C, preferably in the range of from 15 to 30 °C, more preferably in the range of from 15 to 25 °C, maintained at this value for a period of time, lowered in second sub-step to a value in the range of from 5 to less than 15 °C, preferably in the range of from 5 to 12.5 °C, and maintained at this value for a period of time.

58. The process of any one of embodiments 48 to 57, wherein removing water from the mix- ture comprises subjecting the mixture to a pressure of less than 1 bar(abs), preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more preferably in the range of from 20 to 800 mbar(abs), more preferably in the range of from 30 to 700 mbar(abs).

59. The process of any one of embodiments 48 to 58, wherein the seed crystals of 2'-0- fucosyl lactose are seed crystals of crystalline form II of 2'-0-fucosyl lactose, seed crystals of one or more crystalline forms of 2'-0-fucosyl lactose other than form II, or a mixture of seed crystals of crystalline form II of 2'-0-fucosyl lactose and seed crystals of one or more crystalline forms of 2'-0-fucosyl lactose other than form II.

60. The process of any one of embodiments 48 to 59, wherein to the mixture obtained from (a) and subjected to (b), the seed crystals are added in an amount in the range of from 0.01 to 5 weight-%, preferably in the range of from 0.02 to 1 weight-%, based on the amount of 2'-0-fucosyl lactose present in the mixture.

61. The process of any one of embodiments 18 to 60, wherein the crystallization conditions according to (b) comprise continuous, semi-continuous or batch crystallization, preferably continuous crystallization.

62. The process of embodiment 61 , wherein the continuous crystallization according to (b) comprises

(b1 ) continuously feeding the mixture obtained from (a), optionally after concentration as defined in any one of embodiments 44 to 47, to a continuously operated crystalliza- tion apparatus, wherein during crystallization, the crystallization mixture contained in the continuously operated crystallization apparatus contains the crystalline form II of 2'-0-fucosyl lactose in an amount from 5 to 60 weight-%, preferably in the range of from 10 to 45 weight-%, more preferably in the range of from 20 to 40 weight-%, based on the total weight of the crystallization mixture; (b2) continuously removing water from the crystallization mixture contained in the crystal- lization apparatus, preferably by evaporation, more preferably by evaporation a at a pressure of less than 1 bar (abs);

(b3) continuously removing the crystallization mixture containing 2'-0-fucosyl lactose from the crystallization apparatus.

63. The process of embodiment 62, wherein according to (b3), the crystallization mixture con- taining 2'-0-fucosyl lactose is removed from the crystallization apparatus in two or more streams, preferably in two streams, wherein a first stream is subjected to (c) and a second stream is recycled to (b1), wherein the volume ratio of the volume of the entire crystalliza- tion mixture removed from the crystallization apparatus relative to the volume of the first stream, V:V1 , is at least 4:1 , preferably at least 7:1 , more preferably at least 10:1.

64. The process of embodiment 63, wherein V:V1 is in the range of from 4:1 to 200:1 , prefer- ably in the range of from 7:1 to 80:1 , more preferably in the range of from 10:1 to 60:1.

65. The process of any one of embodiments 18 to 64, wherein separating according to (c) comprises

(d) subjecting the crystallization mixture obtained from (b) to a solid-liquid separation, obtaining solid material comprising the crystalline form II of 2'-0-fucosyl lactose, said solid-liquid separation preferably comprising one or more of filtration and cen- trifugation;

(c2) preferably subjecting the solid material obtained from (C1 ) to washing, preferably with one or more of water, an anti-solvent for 2'-0-fucosyl lactose, the mother liquor of a subsequent crystallization stage as defined in embodiment 66, and a saturated aqueous solution of 2'-0-fucosyl lactose, said washing being carried out at least once;

(c3) optionally subjecting the preferably washed solid material to drying in a gas atmos- phere, preferably at a temperature of the gas atmosphere in the range of from 10 to 80 °C, more preferably in the range of from 15 to 70 °c, more preferably in the range of from 20 to 65 °C, more preferably in the range of from 40 to 60 °C, preferably at a pressure of less than 1 bar(abs), more preferably in the range of from 2 to 999 mbar(abs), more preferably in the range of from 5 to 900 mbar(abs).

66. The process of any one of embodiments 18 to 65, comprising at least two subsequent stages (1) and (2), wherein stage (1) comprises

(b-1 ) subjecting the mixture obtained from (a) to crystallization conditions, obtaining a crystallization mixture (1 ) comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor (1);

(c-1) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b-1), obtaining the mother liquor (1 ), and dissolving the crystalline form II of 2'- O-fucosyl lactose in an aqueous mixture (1);

and wherein stage (2) comprises (b-2) subjecting the aqueous solution obtained from (c-1) to crystallization conditions, ob- taining a crystallization mixture (2) comprising the crystalline form II 2'-0-fucosyl lac- tose in its mother liquor (2);

(c-2) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b-2), obtaining the mother liquor (2).

67. The process of embodiment 66, wherein the crystallization is carried out continuously or semi-continuously and wherein the aqueous mixture in which the crystalline form II of 2'- O-fucosyl lactose is dissolved according to (c-1) comprises, preferably consists of, at least a portion of the mother liquor (2) and preferably additional water.

68. The process of embodiment 66 or 67, comprising n subsequent stages, n > 2, wherein a given stage (i), 1 < i < n, comprises

(b-i) subjecting the aqueous solution obtained from (c-(i-1 )) to crystallization conditions, obtaining a crystallization mixture (i) comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor (i);

(c-i) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b-i), obtaining the mother liquor (i), and dissolving the crystalline form II of 2'- O-fucosyl lactose in an aqueous mixture (i);

wherein the crystallization is preferably carried out continuously or semi-continuously and wherein the aqueous mixture in which the crystalline form II of 2'-0-fucosyl lactose is dis- solved according to (c-i) comprises, preferably consists of, at least a portion of the mother liquor (i+1) and preferably additional water.

69. The process of any one of embodiments 66 to 68, wherein the mother liquor (1) is sub- jected to crystallization.

70. The process of any one of embodiments 18 to 69, wherein the crystalline form II of 2'-0- fucosyl lactose obtained from (c) is subjected to water vapour, preferably in a vessel wherein the interior space of the vessel has, or is maintained at, an elevated humidity relative to that outside the vessel, said elevated humidity in the interior space of the vessel preferably being or being maintained within the range of 60 to 100 % relative humidity, wherein said subjecting to water vapour is preferably carried out at a pressure of less than 1 bar(abs).

71. Crystalline form II of 2'-0-fucosyl lactose, preferably crystalline form II of 2'-0-fucosyl lac- tose according to any one of embodiments 1 to 17, obtainable or obtained by a process according to any one of embodiments 18 to 70.

7T. A solid chemical composition, wherein from 90 to 100 weight- % of said composition con- sist of crystalline form II of 2'-0-fucosyl lactose, preferably the solid chemical composition according to any one of embodiments T to 17', obtainable or obtained by a process ac cording to any one of embodiments 18 to 70. 72. A nutritional formulation, comprising the crystalline form II according to any one of the embodiments 1 to 17 or 71 , or the solid chemical composition according to any one of embodiments 1 ' to 17' or 71'.

73. The nutritional formulation of embodiment 72, further comprising water and optionally one or more of lactose, monosaccharides, di- and oligosaccharides other than 2'-0-fucosyl lactose, vitamins, minerals, prebiotics, and probiotics, wherein the formulation is not mammal milk.

74. A cosmetic formulation, comprising the crystalline form II according to any one of the em- bodiments 1 to 17 or 71 , or the solid chemical composition according to any one of em- bodiments T to 17' or 7T.

75. A pharmaceutical formulation, comprising the crystalline form II according to any one of the embodiments 1 to 17 or 71 , or the solid chemical composition according to any one of embodiments T to 17' or 7G.

76. The pharmaceutical formulation of embodiment 75 for use in the treatment and/or the pre- vention of diseases or disorders of the brain, the immune system, the microbiotic envi- ronment of the skin and/or the intestines, the general physical ability; and/or of pathogenic attacks within humans or animals.

77. The formulation of any one of embodiments 72 to 76, exhibiting an improved storage sta- bility when compared to a formulation comprising a crystalline form of 2'-0-fucosyl lactose other than the crystalline form II.

78. The formulation of any one embodiments 72 to 77, comprising the crystalline form II of 2'- O-fucosyl lactose at an a:b anomeric ratio in the range of from 40:60 to 60:40, preferably in the range of from 45:55 to 55:45, more preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49, more preferably of 50:50, after a storage for of at least 3 months, preferably after a storage in the range of from 3 to 36 months, more preferably after a storage in the range of from 3 to 24 months, more preferably after a storage in the range of from 4 to 9 months, at a storage tempera- ture in the range of from 25 to 45 °C and a relative humidity in the range of from 55 to 75 %.

79. Use of the crystalline form II according to any one of the embodiments 1 to 17 or 71 , or the solid chemical composition according to any one of embodiments T to 17' or 7T, for preparing

A) a nutritional formulation according to embodiment 72 to boost the development and/or improvement of the brain, the immune system, intestine microbiotic environ- ment of an infant or baby; and/or the improvement and/or maintenance of the brain, the immune system, intestine microbiotic environment, general physical ability and/or the resistancy against pathogenic attacks within a human child or adult;

and/or

B) a cosmetic formulation according to embodiment 73 for the maintenance and/or im- provement of the skin including elasticity, resistancy against pathogenic attacks and/or the microbiota of the skin;

and/or

C) a pharmaceutical formulation according to embodiment 74 for the treatment and/or the prevention of diseases or disorders of the brain, the immune system, the micro- biotic environment of the skin and/or the intestines, the general physical ability; and/or pathogenic attacks within humans or animals.

80. A method of treating a nutritional formulation according to embodiment 72 or 73, wherein the formulation is kept at an elevated temperature of at least 30 °C, preferably at least 35 °C, for a period of at least 3 min, preferably at least 5 min, more preferably at least 7 min.

Chemical composition

As mentioned above, the present invention further relates to a solid chemical composition, wherein from 90 to 100 weight- % of said composition consist of crystalline form II of 2'-0-fucosyl lactose of formula (I)

wherein said crystalline form exhibits an a:b anomeric ratio in the range of from 40:60 to 60:40 determined by ¹³ C-NMR, wherein said composition has an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Kai _,2 radiation having a wavelength of 0.15419 nm.

Preferably, from 91 to 100 weight-%, more preferably from 92 to 100 weight-%, more preferably from 93 to 100 weight-%, more preferably from 94 to 100 weight-%, more preferably from 95 to 100 weight-%, more preferably from 96 to 100 weight-% of said composition consist of said crystalline form. More preferably, from 97 to 100 weight-% or from 98 to 100 weight-% or from 99 to 100 weight-% of said composition consist of said crystalline form. It is further preferred that said X-ray powder diffraction pattern further comprises one or more reflections at 20 angles (1.70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably two or more reflections at 20 angles (1.70 ±

0.20)°, (11.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably three or more reflections at 20 angles (1.70 ± 0.20)°, (11.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably four or more reflec- tions at 20 angles (1.70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably five or more reflections at 20 angles (1.70 ± 0.20)°, (11.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably six reflections at 20 angles (1.70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°.

As far as the said a:b anomeric ratio is concerned, it is preferred that it is in the range of from 45:55 to 55:45, more preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more prefer- ably in the range of from 49:51 to 51 :49. More preferably, the a:b anomeric ratio is in the range of from 49.2:50.8 to 50.8:49.2, more preferably in the range of from 49.4:50.6 to 50.6:49.4, more preferably in the range of from 49.6:50.4 to 50.4:49.6, more preferably in the range of from 49.8:50.2 to 50.2:49.8, more preferably in the range of from 49.9:50.1 to 50.1 :49.9. More pref- erably, the a:b anomeric ratio is 50:50.

It is further preferred that said chemical composition has total content of saccharides other than 2'-0-fucosyl lactose in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 2 weight-%, more preferably more in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, such as from 0 to 0.5 weight-% or from 0 to 0.4 weight-% or from 0 to 0.3 weight-% or from 0 to 0.2 weight-% or from 0 to 0.1 weight-%, based on the total weight of all saccharides comprised in said composition. Preferably, the saccharides other than 2'-0-fucosyl lactose are at least one monosaccharide or at least one oligosaccharide other than 2'-0-fucosyl lactose or a mixture of at least one monosaccharide and at least one oligo saccharide other than 2'-0-fucosyl lactose.

More preferably, the at least one saccharide other than 2'-0-fucosyl lactose comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and optionally one or more further oligosaccharides other than those mentioned before, more preferably comprises, more preferably is, one or more of lactose, fuco- sylated lactose, fucose, galactose, glucose, lactulose and fucosylated lactulose, wherein the fucosylated lactose preferably comprises, more preferably is, difucosyl lactose, and wherein the difucosyl lactose preferably comprises, more preferably is, one or more of 2’,2”-0-difucosyl lac- tose and 2’,3-O-difucosyl lactose.

Further, it is preferred that said chemical composition has a total content of organic compounds other than 2'-0-fucosyl lactose in the range of from 0 to 9 weight-%, preferably in the range of from 0 to 8 weight-%, more preferably in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 3 weight-%, more preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, such as from 0 to 1 weight-% or from 0 to 0.8 or from 0 to 0.6 weight-% or from 0 to 0.4 weight-% or from 0 to 0.2 weight-%, based on the total weight of all organic corn- pounds comprised in said chemical composition.

Yet further, it is preferred that said chemical composition has a total content of organic solvents in the range of from 0 to 3 weight-%, preferably in the range of from 0 to 2 weight-%, more pref- erably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight- %, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.01 weight-%, based on the total weight of said composition. As far as said solvents are concerned, it is preferred that they have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar(abs). More preferably, said organic solvents are one or more of one or more organic alcohols, one or more alkanoic acids, and a mixture of one or more organic alcohols, one or more alkanoic acids, wherein the one or more organic alcohols are preferably one or more of C1 , C2, C3 and C4 al- cohols and wherein the one or more one or more alkanoic acids are preferably one or more of C1 , C2, C3 and C4 alkanoic acids.

It is further preferred that said chemical composition has a water content in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, based on the total weight of said composition, determined by Karl Fischer titration.

The amount of any crystal water contained in the crystalline form of 2'-0-fucosyl lactose is pref- erably the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.02 weight-%, based on the total weight of said composition, determined by Karl Fischer titration.

Preferably, said chemical composition is in the form of crystals having a ratio length dhickness of at most 10:1 , more preferably of at most 5:1 , more preferably of at most 2:1 , such as in the range of from 1 :10 to 10:1 or in the range of from 1 :5 to 5:1 or in the range of from 1 :2 to 2:1. More preferably, said ratio lengthdhickness is in the range of from 1 :1 to 10:1 , more preferably in the range of from 1.1 :1 to 5:1 , more preferably in the range of from 1.2:1 to 2:1.

Also preferably, said chemical composition is in the form of crystals having an average particle size in the range of from 0.2 to 1.5 mm, more preferably in the range of from 0.3 to 1.0 mm, wherein the average particle size is the weight average particle size. It is preferred that from 0 to 10 weight-% of the particles have a size of less than 100 micrometer. Crystalline form

As described above, the present invention further relates to a crystalline form II of 2'-0-fucosyl lactose of formula (I)

wherein said crystalline form exhibits an a:b anomeric ratio in the range of from 40:60 to 60:40 determined by ¹³ C-NMR, wherein said composition has an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Ka-1 ,2 radiation having a wavelength of 0.15419 nm.

It is further preferred that said X-ray powder diffraction pattern further comprises one or more reflections at 20 angles (1 .70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21 .70 ± 0.20)°, more preferably two or more reflections at 20 angles (1 .70 ±

0.20)°, (1 1 .94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21 .70 ± 0.20)°, more preferably three or more reflections at 20 angles (1.70 ± 0.20)°, (1 1 .94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21 .70 ± 0.20)°, more preferably four or more reflec- tions at 20 angles (1 .70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°, more preferably five or more reflections at 20 angles (1.70 ± 0.20)°, (1 1 .94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21 .70 ± 0.20)°, more preferably six reflections at 20 angles (1.70 ± 0.20)°, (1 1.94 ± 0.20)°, (15.22 ± 0.20)°, (18.32 ± 0.20)°, (20.63 ± 0.20)° and (21.70 ± 0.20)°.

As far as the said a:b anomeric ratio is concerned, it is preferred that it is in the range of from 45:55 to 55:45, more preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more prefer ably in the range of from 49:51 to 51 :49. More preferably, the a:b anomeric ratio is in the range of from 49.2:50.8 to 50.8:49.2, more preferably in the range of from 49.4:50.6 to 50.6:49.4, more preferably in the range of from 49.6:50.4 to 50.4:49.6, more preferably in the range of from 49.8:50.2 to 50.2:49.8, more preferably in the range of from 49.9:50.1 to 50.1 :49.9. More pref- erably, the a:b anomeric ratio is 50:50.

Preferably, said crystalline form has a purity with regard to said crystalline form in the range of from 97 to 100 weight- % or in the range of from 98 to 100 weight- % or in the range of from 99 to 100 weight-%. It is further preferred that said crystalline form has total content of saccharides other than 2'-0- fucosyl lactose in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 2 weight-%, preferably more in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, such as from 0 to 0.5 weight-% or from 0 to 0.4 weight-% or from 0 to 0.3 weight-% or from 0 to 0.2 weight-% or from 0 to 0.1 weight-%, based on the total weight of all saccharides comprised in said crystalline form. Preferably, the saccharides other than 2'-0- fucosyl lactose are at least one monosaccharide or at least one oligosaccharide other than 2'-0- fucosyl lactose or a mixture of at least one monosaccharide and at least one oligosaccharide other than 2'-0-fucosyl lactose comprises, more preferably is, one or more of lactose, fucosyl- ated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and optionally one or more further oligosaccharides other than those mentioned before, more preferably comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lac- tulose and fucosylated lactulose, wherein the fucosylated lactose preferably comprises, more preferably is, difucosyl lactose, and wherein the difucosyl lactose preferably comprises, more preferably is, one or more of 2’,2”-0-difucosyl lactose and 2’,3-O-difucosyl lactose.

Further, it is preferred that said crystalline form has a total content of organic compounds other than 2'-0-fucosyl lactose in the range of from 0 to 9 weight-%, preferably in the range of from 0 to 8 weight-%, more preferably in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more pref- erably in the range of from 0 to 4 weight-%, more preferably in the range of from 0 to 3 weight- %, more preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, such as from 0 to 1 weight-% or from 0 to 0.8 or from 0 to 0.6 weight-% or from 0 to 0.4 weight-% or from 0 to 0.2 weight-%, based on the total weight of all organic compounds comprised in said crystalline form.

Yet further, it is preferred that said crystalline form has a total content of organic solvents in the range of from 0 to 3 weight-%, preferably in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.01 weight-%, based on the total weight of said crystalline form. As far as said solvents are concerned, it is preferred that they have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar(abs). More preferably, said organic solvents are one or more of one or more organic alcohols, one or more alkanoic acids, and a mixture of one or more organic alcohols, one or more alkanoic ac- ids, wherein the one or more organic alcohols are preferably one or more of C1 , C2, C3 and C4 alcohols and wherein the one or more one or more alkanoic acids are preferably one or more of C1 , C2, C3 and C4 alkanoic acids.

It is further preferred that said crystalline form has a crystal water content in the range of from 0 to 2 weight-%, more preferably in the range of from 0 to 1 weight-%, more preferably in the range of from 0 to 0.5 weight-%, more preferably in the range of from 0 to 0.1 weight-%, more preferably in the range of from 0 to 0.05 weight-%, more preferably in the range of from 0 to 0.02 weight-%, based on the total weight of said crystalline form, determined by Karl Fischer titration. The total amount of water present is preferably in the range of from 0 to 7 weight-%, more preferably in the range of from 0 to 6 weight-%, more preferably in the range of from 0 to 5 weight-%, more preferably in the range of from 0 to 4 weight-%, based on the total weight of said crystalline form, determined by Karl Fischer titration.

Preferably, said crystalline form is in the form of crystals having a ratio length dhickness of at most 10:1 , more preferably of at most 5:1 , more preferably of at most 2:1 , such as in the range of from 1 :10 to 10:1 or in the range of from 1 :5 to 5:1 or in the range of from 1 :2 to 2:1. More preferably, said ratio length:thickness is in the range of from 1 :1 to 10:1 , more preferably in the range of from 1.1 :1 to 5:1 , more preferably in the range of from 1.2:1 to 2:1.

Also preferably, said crystalline form is in the form of crystals having an average particle size in the range of from 0.2 to 1.5 mm, more preferably in the range of from 0.3 to 1.0 mm, wherein the average particle size is the weight average particle size. It is preferred that from 0 to 10 weight-% of the particles have a size of less than 100 micrometer.

Process

Further, the present invention relates to a process for preparing crystalline form II of 2'-0- fucosyl lactose (2’-FL) of formula (I)

having an X-ray powder diffraction pattern comprising three reflections at 20 angles (13.65 ± 0.20)°, (16.98 ± 0.20)° and (18.32 ± 0.20)°, determined at a temperature of 25 °C with Cu-Ka-1 ,2 radiation having a wavelength of 0.15419 nm, preferably to a process for preparing the crystal- line form II of 2'-0-fucosyl lactose as described above, in particular in any one of embodiments 1 to 17, and/or for preparing a chemical composition as described above, in particular in any one of embodiments T to 17’, said process comprising

(a) providing an aqueous mixture comprising a saccharide composition dissolved in water, wherein from 70 to 100 weight-% of the saccharide composition consist of 2'-0-fucosyl lactose; and

adjusting the temperature of the provided mixture to a value in the range of from 20 to 95 °C at ambient pressure and maintaining the temperature of the mixture at a value in this range until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio in the range of from 40:60 to 60:40, determined by ¹³ C-NMR;

(b) subjecting the mixture obtained from (a) to crystallization conditions, obtaining a crystalli zation mixture comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor;

(c) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b)·

The necessary time needed until the mixture exhibits the preferred ratio of alpha and beta anomers can be determined a small number of experiments; the examples given provide the ranges which work, from which further variations in time depending on the actual conditions chosen can be easily and without inventive skill derived from.

Chemical composition of the mixture provided in (a)

Generally, the concentration of the 2'-0-fucosyl lactose in the mixture provided in (a) is not sub- ject to specific restrictions. Preferably, in the mixture provided in (a), the concentration of the 2'- O-fucosyl lactose is in the range of from 200 to 750 g/L, more preferably in the range of from 250 to 650 g/L, more preferably in the range of from 300 to 600 g/L, more preferably in the range of from 350 to 550 g/L, more preferably in the range of from 400 to 500 g/L, such as from 400 to 450 g/L or from 425 to 475 g/L or from 450 to 500 g/L.

Preferably, the saccharide composition according to (a) additionally comprises at least one sac- charide other than 2'-0-fucosyl lactose, more preferably at least one monosaccharide or at least one oligosaccharide other than 2'-0-fucosyl lactose or a mixture of at least one monosaccharide and at least one oligosaccharide other than 2'-0-fucosyl lactose. It is preferred that from 70 to 99.5 weight-%, more preferably from 75 to 95 weight-%, more preferably from 78 to 92 weight- % of the saccharide composition according to (a) consist of 2'-0-fucosyl lactose, based on the total amount of all saccharides comprised in the saccharide composition, preferably all mono- saccharides and oligosaccharides comprised in the saccharide composition. Further preferably, from 30 to 0.5 weight-%, more preferably from 25 to 5 weight-%, more preferably from 22 to 8 weight-% of the saccharide composition according to (a) consist of the at least one saccharide other than 2'-0-fucosyl lactose, more preferably consist of the at least monosaccharide or the at least one oligosaccharide other than 2'-0-fucosyl lactose or the mixture of at least one mono- saccharide and at least one oligosaccharide other than 2'-0-fucosyl lactose. While not being subject to any specific restrictions, it is preferred that the at least one saccharide other than 2'- O-fucosyl lactose comprises, more preferably is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose, fucosylated lactulose, and optionally one or more further oligosaccharides other than those mentioned before, more preferably comprises, more prefera- bly is, one or more of lactose, fucosylated lactose, fucose, galactose, glucose, lactulose and fucosylated lactulose.

According to a first preferred embodiment of the present invention, the at least one saccharide other than 2'-0-fucosyl lactose comprises fucosylated lactose, preferably difocusyl lactose. More preferably, said fucosylated lactose comprises difucosyl lactose, wherein the difucosyl lactose preferably comprises one or more of 2’,2”-0-difucosyl lactose and 2’,3-O-difucosyl lac- tose. Preferably, the saccharide composition according to (a) comprises the fucosylated lactose in an amount in the range of from 0.5 to 10, more preferably in the range of from 0.5 to 8 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 0.5 to 4 weight-%, such as from 0.5 to 1.5 weight-% or from 1.0 to 2.0 or from 1.5 to 2.5 weight-% or from 2.0 to 3.0 weight-% or from 2.5 to 3.5 weight-% or from 3.0 to 4.0 weight-% or from 3.5 to 4.5 weight-%, based on the total amount of all saccharides comprised in the saccha- ride composition, preferably all monosaccharides and oligosaccharides comprised in the sac- charide composition.

According to a second preferred embodiment of the present invention, the at least one saccha- ride other than 2'-0-fucosyl lactose comprises lactulose, or fucosylated lactulose, or a mixture of lactulose and fucosylated lactulose. Preferably, the saccharide composition according to (a) comprises said lactulose, or said fucosylated lactulose, or said mixture of lactulose and fucosyl- ated lactulose in an amount in the range of from 0.5 to 10, preferably in the range of from 0.5 to 8 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 0.5 to 4 weight-%, such as from 0.5 to 1.5 weight-% or from 1.0 to 2.0 or from 1.5 to 2.5 weight-% or from 2.0 to 3.0 weight-% or from 2.5 to 3.5 weight-% or from 3.0 to 4.0 weight-%, based on the total amount of all saccharides comprised in the saccharide composi- tion, preferably all monosaccharides and oligosaccharides comprised in the saccharide compo- sition.

According to the present invention, it is preferred that from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more preferably from 99.9 to 100 weight-% of the saccharide mixture according to (a) consist of 2'-0-fucosyl lactose and the at least one saccharide other than 2'-0-fucosyl lactose, preferably consist of (i) 2'-0-fucosyl lactose and (ii) the at least one monosaccharide or the at least one oligosaccharide other than 2'-0-fucosyl lactose or a mixture of at least one monosaccharide and at least one oligosaccha- ride other than 2'-0-fucosyl lactose.

Further preferably, the mixture provided according to (a) further comprises one or more organic solvents. Preferably, the one or more organic solvents have one or more boiling points in the range of from 30 to 250 °C at a pressure of 1 bar. Preferably, the one or more organic solvents are at least one organic alcohols, or at least one alkanoic acid, or a mixture of at least one or ganic alcohols and at least one alkanoic acids, wherein the at least one organic alcohol is more preferably one or more of C1 , C2, C3 and C4 alcohols and wherein the at least one alkanoic acid is preferably one or more of C1 , C2, C3 and C4 alkanoic acids. In the mixture provided according to (a), the weight ratio of the organic solvents relative to the water is in the range of from 0:1 to 0.05:1 , preferably in the range of from 0:1 to 0.02:1 weight-%, more preferably in the range of from 0:1 to 0.01 :1 , wherein said weight ratio relates to the total amount of all organic solvents in said mixture. It is preferred that from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more preferably from 99.9 to 100 weight- % of the mixture provided according to (a) consist of the water, the saccharide composi- tion and optionally the one or more organic solvents as described above.

It is further preferred that the 2'-0-fucosyl lactose comprised in the saccharide composition comprised in the mixture provided according to (a) exhibits an a:b anomeric ratio in the range of from 0:100 to 100:0. According to a first preferred embodiment in this respect, the a:b anomeric ratio is in the range of from 0:100 to 35:65, more preferably in the range of from 10:90 to 30:70, more preferably in the range of from 15:85 to 25:75. According to a first preferred embodiment in this respect, the a:b anomeric ratio is in the range of from 100:0 to 65:35, more preferably in the range of 90:10 to 70:30, more preferably in the range of from 85:15 to 75:25.

Providing the aqueous mixture according to (a)

Generally, the aqueous mixture comprising the saccharide composition is provided according to (a) according to any conceivable and suitable method, such as a chemical method or a bio- chemical method, wherein a biochemical method is preferred. Preferably, said biochemical method comprises enzymatically biocatalytically fucosylating lactose to obtain 2'-0-fucosyl lac- tose. A preferred biochemical method according to the present invention comprises a fermenta- tion process which preferably comprises

(i) preparing a fermentation broth comprising a culture medium and an aqueous supernatant thereof, wherein the supernatant comprises 2'-0-fucosyl lactose at a concentration of at least 25 g/L, preferably in the range of from 25 to 150 g/L, more preferably in the range of from 25 to 120 g/L, and wherein the supernatant optionally comprises difucosyl lactose, preferably at a concentration in the range of from 1.5 to 20 weight- % based on the amount of 2'-0-fucosyl lactose comprised in the supernatant;

(ii) separating the supernatant from the culture medium;

(iii) optionally subjecting the supernatant obtained from of (ii) to a post-treatment comprising demineralization and/or chromatography.

Preferably, said demineralization comprises contacting the supernatant with one or more ion exchange resins, preferably comprises contacting the supernatant with at least one cation ex- change resin which is preferably in H ⁺ form and wherein preferably at least one, more preferably all of the cation exchange resins, is a strong cation exchange resin, and with at least one anion exchanges resin which is preferably in free base form and wherein preferably at least one of the anion exchange resins, preferably all of the anion exchange resins, is a strong exchange resin. Further preferably, said demineralization comprises subjecting the supernatant to electrodialy- sis. With respect to said conceivable and suitable chemical and biochemical methods, reference is made to the respective portion of the description hereinabove.

According to the present invention, it is particularly preferred that according to (a), the tempera- ture of the provided mixture is maintained until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio in the range of from 45:55 to 55:45, preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49. More preferably, the temperature of the provided mixture is maintained until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio in the range of from 49.2:50.8 to 50.8:49.2, more preferably in the range of from 49.4:50.6 to 50.6:49.4, more preferably in the range of from 49.6:50.4 to

50.4:49.6, more preferably in the range of from 49.8:50.2 to 50.2:49.8, more preferably in the range of from 49.9:50.1 to 50.1 :49.9. More preferably, the temperature of the provided mixture is maintained until the 2'-0-fucosyl lactose finally obtained exhibits an a:b anomeric ratio of 50:50.

In this respect, it is preferred that according to (a), the temperature of the provided mixture is adjusted to a value in the range of from 20 to 90 °C, more preferably in the range of from 30 to 85 °C, more preferably in the range of from 40 to 80 °C, more preferably in the range of from 50 to 75 °C, more preferably in the range of from 60 to 70 °C, in each case at ambient pressure.

Concentrating the mixture before crystallization

According to the present invention, it may be preferred that prior to (b) and/or during (b), the mixture is concentrated to a concentration of the 2'-0-fucosyl lactose of at least 500 g/L, more preferably in the range of from 500 to 750 g/L, more preferably in the range of from 510 to 720 g/L, more preferably in the range of from 550 to 720 g/L, more preferably in the range of from 600 to 720 g/L, more preferably in the range of from 630 to 720 g/L, more preferably in the range of from 650 to 720 g/L. Generally, said concentrating of said mixture can be carried out by any suitable method or combination of two or more suitable methods. In particular, when concentrating said mixture, it is preferred that water is separated from said mixture. In this re- spect, it is preferred that water is separated from the mixture at a pressure of less than 1 bar(abs), more preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more preferably in the range of rom 50 to 800 mbar(abs). Prefera- bly, the temperature of the mixture during separation of water is at least 20 °C, more preferably in the range of from 20 to 105 °C, more preferably in the range of from 25 to 105 °C, more pref- erably in the range of from 30 to 105 °C, more preferably in the range of from 35 to 105 °C, more preferably in the range of from 60 to 105 °C, more preferably in the range of from 60 to 100 °C, more preferably in the range of from 60 to 95 °C.

Crystallization according to (b)

As far as the crystallization according to (b) is concerned, it is preferred according to the present invention that the respective crystallization conditions according to (b) comprise one or more of supersaturating the mixture;

adding an anti-solvent for 2'-0-fucosyl lactose;

lowering the temperature of the mixture;

stirring the mixture;

adding seed crystals of 2'-0-fucosyl lactose to the mixture;

removing water from the mixture. Supersaturation

According to the present invention, it is preferred that the crystallization comprises supersaturat- ing the mixture. Preferably, in the crystallization mixture during crystallization according to (b), said supersaturation is characterized by a ratio c:c ^* in the mixture in the range of from

1.00001 :1 to 1.5:1. As to this ratio, the parameter c/(g/L) is the concentration of 2'-0-fucosyl lactose dissolved in the water comprised in the crystallization mixture under the given crystalli zation conditions, and the parameter c ^* /(g/L) is the equilibrium solubility of 2'-0-fucosyl lactose in water under these conditions. More preferably, said ratio c:c ^* is in the range of from

1.00005:1 to 1.4:1 , more preferably in the range of from 1.0001 :1 to 1.3:1 , more preferably in the range of from 1.0005:1 to 1.2:1 , more preferably in the range of from 1.001 :1 to 1.2:1 , more preferably in the range of from 1.002:1 to 1.15:1. Preferably, when adjusting the supersaturation of the mixture, water is removed from the mixture. This water removal can be carried out by any suitable method.

According to a first preferred embodiment if the present invention in this respect, removing wa- ter from the mixture comprises subjecting the mixture to a pressure of less than 1 bar(abs), more preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more preferably in the range of from 50 to 800 mbar(abs). In this respect, a first preferred sub-embodiment of the present invention relates to said process wherein the water is removed from the mixture at a temperature of the mixture of at least 20 °C, more pref- erably in the range of from 20 to 105 °C, more preferably in the range of from 25 to 105 °C, more preferably in the range of from 30 to 100 °C, more preferably in the range of from 35 to 95 °C. In this respect, a second preferred sub-embodiment of the present invention relates to said process wherein the water is removed from the mixture at a temperature of the mixture in the range of from 60 to 105 °C, preferably in the range of from 61 to 100 °C, more preferably in the range of from 62 to 95 °C, more preferably in the range of from 63 to 90 °C, more preferably in the range of from 63 to 85 °C. According to a second preferred embodiment if the present in- vention in this respect, the process comprises removing water from the mixture at a pressure of 1 bar(abs) and a temperature of the mixture in the range of from 0 to 90 °C, more preferably in the range of from 60 to 90 °C, more preferably in the range of from 60 to 80 °C, more preferably in the range of from 60 to 70 °C.

Other general disclosure regarding crystallization conditions according to (b)

As far as said anti-solvent for 2'-0-fucosyl lactose is concerned, it is preferred that it is one or more of at least one C1 to C6 alcohol, such as a C1 alcohol, a C2 alcohol, a C3 alcohol, a C4 alcohol, a C5 alcohol, a C6 alcohol, and at least one organic acid, wherein the at least one C1 to C6 alcohol is preferably selected from the group consisting of methanol, ethanol, at least one propanol, at least one butanol, and at least one hexanol, and wherein the at least one organic acid is preferably one or more of acetic acid and propionic acid. In case the crystallization conditions according to (b) comprise lowering the temperature of the mixture, it is preferred that the temperature of the mixture is lowered from a value of at least 60 °C to a value of below 60 °C, preferably from a value of at least 60 °C to a value in the range of from 0 to 55 °C. In this respect, it may be preferred that the temperature of the mixture is low- ered step-wise to a value of below 60 °C, more preferably in two or more steps, wherein in a first step, the temperature of the mixture is preferably lowered to a value in the range of from 40 to 55 °C and the temperature is maintained at this value for a period of time, and wherein in a second step, the temperature of the mixture is preferably lowered to a value in the range of from 0 to less than 40 °C, more preferably in the range of from 5 to 35 °C, wherein according to said second step, the temperature is optionally lowered in a first sub-step to a value in the range of from 15 to 35 °C, preferably in the range of from 15 to 30 °C, more preferably in the range of from 15 to 25 °C, maintained at this value for a period of time, lowered in second sub-step to a value in the range of from 5 to less than 15 °C, preferably in the range of from 5 to 12.5 °C, and maintained at this value for a period of time.

In case the crystallization conditions according to (b) comprise removing water, it is preferred that said removing of water comprises subjecting the mixture to a pressure of less than 1 bar(abs), more preferably in the range of from 5 to 999 mbar(abs), more preferably in the range of from 10 to 900 mbar(abs), more preferably in the range of from 20 to 800 mbar(abs), more preferably in the range of from 30 to 700 mbar(abs).

In case the crystallization conditions according to (b) comprise adding seed crystals, it is pre- ferred that said seed crystals of 2'-0-fucosyl lactose are seed crystals of crystalline form II of 2'- O-fucosyl lactose, seed crystals of one or more crystalline forms of 2'-0-fucosyl lactose other than form II, or a mixture of seed crystals of crystalline form II of 2'-0-fucosyl lactose and seed crystals of one or more crystalline forms of 2'-0-fucosyl lactose other than form II. Preferably, the seed crystals are added to the mixture obtained from (a) and subjected to (b) in an amount in the range of from 0.01 to 5 weight-%, more preferably in the range of from 0.02 to 1 weight- %, based on the amount of 2'-0-fucosyl lactose present in the mixture. Alternatively, also an amorphous form of 2’-FL can be used instead or in combination with crystals of 2’-FL.

Generally, the crystallization according to (b) can be performed continuously, semi-continuously or as batch crystallization. According to a preferred embodiment of the present invention, the crystallization conditions according to (b) comprise continuous crystallization. In this case, it is further preferred the continuous crystallization according to (b) comprises

(b1 ) continuously feeding the mixture obtained from (a), optionally after concentration as de- fined in any one of embodiments 44 to 47, to a continuously operated crystallization appa- ratus, wherein during crystallization, the crystallization mixture contained in the continu- ously operated crystallization apparatus contains the crystalline form II of 2'-0-fucosyl lac- tose in an amount from 5 to 60 weight-%, preferably in the range of from 10 to 45 weight- %, more preferably in the range of from 20 to 40 weight-%, based on the total weight of the crystallization mixture; (b2) continuously removing water from the crystallization mixture contained in the crystalliza- tion apparatus, preferably by evaporation, more preferably by evaporation a at a pressure of less than 1 bar (abs);

(b3) continuously removing the crystallization mixture containing 2'-0-fucosyl lactose from the crystallization apparatus.

According to (b3), the crystallization mixture containing 2'-0-fucosyl lactose is preferably re- moved from the crystallization apparatus in two or more streams, preferably in two streams, wherein a first stream is subjected to (c) and a second stream is recycled to (b1 ), wherein the volume ratio of the volume of the entire crystallization mixture removed from the crystallization apparatus relative to the volume of the first stream, V:V1 , is at least 4:1 , preferably at least 7:1 , more preferably at least 10:1. More preferably, V:V1 is in the range of from 4:1 to 200:1 , prefer ably in the range of from 7:1 to 80:1 , more preferably in the range of from 10:1 to 60:1. Con- ceivable ranges are from 10:1 to 30:1 or from 20:1 to 40:1 or from 30:1 to 50:1 or from 40:1 to 60:1.

Separation according to (c)

As far as the separation according to (c) is concerned, it is preferred that said separating corn- prises

(d) subjecting the crystallization mixture obtained from (b) to a solid-liquid separation, obtain- ing solid material comprising the crystalline form II of 2'-0-fucosyl lactose, said solid-liquid separation preferably comprising one or more of filtration and centrifugation.

In a preferred subsequent step (c2), the solid material obtained from (C1 ) to subjected to wash- ing, preferably with one or more of water, an anti-solvent for 2'-0-fucosyl lactose, the mother liquor of a subsequent crystallization stage as defined in embodiment 66, and a saturated aqueous solution of 2'-0-fucosyl lactose, said washing being carried out at least once.

Optionally, there is a subsequent step (c3) according to which the preferably washed solid ma- terial is subjected to drying in a gas atmosphere, preferably at a temperature of the gas atmos- phere in the range of from 10 to 80 °C, more preferably in the range of from 15 to 70 °c, more preferably in the range of from 20 to 65 °C, more preferably in the range of from 40 to 60 °C, preferably at a pressure of less than 1 bar(abs), more preferably in the range of from 2 to 999 mbar(abs), more preferably in the range of from 5 to 900 mbar(abs).

Further crystallization stages

According to the present invention, the above-described process may comprise one or more further crystallization stages. In this case, it is preferred that the process comprises at least two subsequent stages (1) and (2), wherein stage (1 ) comprises (b-1) subjecting the mixture obtained from (a) to crystallization conditions, obtaining a crystal- lization mixture (1 ) comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor (1 );

(c-1 ) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b-1 ), obtaining the mother liquor (1), and dissolving the crystalline form II of 2'-0-fucosyl lactose in an aqueous mixture (1 );

and wherein stage (2) comprises

(b-2) subjecting the aqueous solution obtained from (c-1) to crystallization conditions, obtaining a crystallization mixture (2) comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor (2);

(c-2) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b- 2), obtaining the mother liquor (2).

As far as this process is concerned, it is preferred that the crystallization is carried out continu- ously or semi-continuously and wherein the aqueous mixture in which the crystalline form II of 2'-0-fucosyl lactose is dissolved according to (c-1) comprises, preferably consists of, at least a portion of the mother liquor (2) and preferably additional water.

Generally, the process of the present invention may comprise n subsequent crystallization stag- es, n > 2, wherein a given stage (i), 1 < i < n, comprises

(b-i) subjecting the aqueous solution obtained from (c-(i-1 )) to crystallization conditions, obtain- ing a crystallization mixture (i) comprising the crystalline form II 2'-0-fucosyl lactose in its mother liquor (i);

(c-i) separating the crystalline form II of 2'-0-fucosyl lactose from the mixture obtained from (b- i), obtaining the mother liquor (i), and dissolving the crystalline form II of 2'-0-fucosyl lac- tose in an aqueous mixture (i);

wherein the crystallization is preferably carried out continuously or semi-continuously and wherein the aqueous mixture in which the crystalline form II of 2'-0-fucosyl lactose is dissolved according to (c-i) comprises, preferably consists of, at least a portion of the mother liquor (i+1) and preferably additional water.

Generally, it may be preferred that the mother liquor (1 ) is subjected to crystallization.

Subjecting crystalline material to water vapour

Further according to the present invention, it may be preferred that the crystalline form II of 2'-0- fucosyl lactose obtained from (c) is subjected to a suitable post-treatment. In this case it is pre- ferred that the crystalline form II of 2'-0-fucosyl lactose obtained from (c) is subjected to water vapour, more preferably in a vessel wherein the interior space of the vessel has, or is main- tained at, an elevated humidity relative to that outside the vessel. It is preferred that said elevat- ed humidity in the interior space of the vessel preferably is, or is maintained, within the range of 60 to 100 % relative humidity. Preferably, said subjecting to water vapour is carried out at a pressure of less than 1 bar(abs). Further, the present invention relates to crystalline form II of 2'-0-fucosyl lactose, preferably crystalline form II of 2'-0-fucosyl lactose according to any one of embodiments 1 to 17 as de- scribed above, obtainable or obtained by a process according to any one of embodiments 18 to 70 as described above.

Yet further, the present invention relates to a solid chemical composition, wherein from 90 to 100 weight- % of said composition consist of crystalline form II of 2'-0-fucosyl lactose, preferably the solid chemical composition according to any one of embodiments 1 ' to 17' as described above, obtainable or obtained by a process according to any one of embodiments 18 to 70 as described above.

Yet further, the present invention relates to a nutritional formulation, comprising the crystalline form II according to any one of the embodiments 1 to 17 or 71 as described above, or the solid chemical composition according to any one of embodiments 1' to 17' or 71 ' as described above. Preferably, said nutritional formulation further comprising water and optionally one or more of lactose, monosaccharides, di- and oligosaccharides other than 2'-0-fucosyl lactose, vitamins, minerals, prebiotics, and probiotics, wherein the formulation is not mammal milk.

Yet further, the present invention relates to a cosmetic formulation, comprising the crystalline form II according to any one of the embodiments 1 to 17 or 71 as described above, or the solid chemical composition according to any one of embodiments 1' to 17' or 71 ' as described above.

Yet further, the present invention relates to a pharmaceutical formulation, comprising the crys- talline form II according to any one of the embodiments 1 to 17 or 71 as described above, or the solid chemical composition according to any one of embodiments 1 ' to 17' or 71' as described above. Preferably, said pharmaceutical formulation of embodiment is for use in the treatment and/or the prevention of diseases or disorders of the brain, the immune system, the microbiotic environment of the skin and/or the intestines, the general physical ability; and/or of pathogenic attacks within humans or animals.

Preferably, said formulations described above exhibit an improved storage stability when corn- pared to a formulation comprising a crystalline form of 2'-0-fucosyl lactose other than the crys- talline form II. Preferably, these formulations comprise the crystalline form II of 2'-0-fucosyl lac- tose at an a:b anomeric ratio in the range of from 40:60 to 60:40, more preferably in the range of from 45:55 to 55:45, more preferably in the range of from 46:54 to 54:46, more preferably in the range of from 47:53 to 53:47, more preferably in the range of from 48:52 to 52:48, more preferably in the range of from 49:51 to 51 :49, more preferably of 50:50, after a storage for of at least 3 months, preferably after a storage in the range of from 3 to 36 months, more preferably after a storage in the range of from 3 to 24 months, more preferably after a storage in the range of from 4 to 9 months, at a storage temperature in the range of from 25 to 45 °C and a relative humidity in the range of from 55 to 75 %.

Still further, the present invention relates to the use of the crystalline form II according to any one of the embodiments 1 to 17 or 71 as described above, or the solid chemical composition according to any one of embodiments 1 ' to 17' or 71 ' as described above, for preparing

A) a nutritional formulation according to embodiment 72 to boost the development and/or improvement of the brain, the immune system, intestine microbiotic environment of an in- fa nt or baby; and/or the improvement and/or maintenance of the brain, the immune sys- tem, intestine microbiotic environment, general physical ability and/or the resistancy against pathogenic attacks within a human child or adult;

and/or

B) a cosmetic formulation according to embodiment 73 for the maintenance and/or improve- ment of the skin including elasticity, resistancy against pathogenic attacks and/or the mi- crobiota of the skin;

and/or

C) a pharmaceutical formulation according to embodiment 74 for the treatment and/or the prevention of diseases or disorders of the brain, the immune system, the microbiotic envi- ronment of the skin and/or the intestines, the general physical ability; and/or pathogenic attacks within humans or animals.

Still further, the present invention relates to a method of treating a nutritional formulation accord- ing to embodiment 72 or 73, wherein the formulation is kept at an elevated temperature of at least 30 °C, preferably at least 35 °C, for a period of at least 3 min, preferably at least 5 min, more preferably at least 7 min.

The invention is described by the following, non-limiting examples.

Examples

Example 1

50 g of 52.5 weight- % solution of 2’-FL raw material in water (52.5 wt-% 2’-FL, 0.9 wt-% lactose, 3-2 wt-% DiFL and 38-5 wt-% water, material from fermentation after filtration, decolorization and desalting) were condensed at 45 °C in vacuo to 40.7 g 2’-FL solution with 64.5 weight-%.

To this not complete clear solution 10 mL of EtOH were added at room temperature and 3 weight-% of seed crystals of form A (from Example 3) were added. It was heated to 79 °C to reflux and stirred for 15 min, then additional 20 mL EtOH were added in 20 min at reflux and the suspension stirred for 20 min at reflux and 2 h at 45 °C. After cooling to room temperature over- night, the crystals were collected, washed twice with 20 mL EtOH/water 90/10 and dried at 40 °C at 10 mbar(abs).

The yield was 24 g crystal in form II. The XRPD pattern is shown in Figure 3a. The a:b anomeric ratio was 0.84:1 (46:54).

Experiments with seeding with Form II or without seeding yielded the same result. As variations to Example 1 above the following are possible:

a. Instead of concentration the 2’-FL-raw material to above 60 weight- % in the syrop as de- tailed in Example 1 , it is also possible to use less high concentrated solutions of 2’-FL raw material of only up to 50 weight- % 2’-FI in solution. The results of the experiment per- formed starting from those less concentrated solutions is basically the same as in Exam- pie 1.

b. As a further possibility, the amount of acetic acid as used in Example 1 can be increased in its amounts up to 3-fold, still leading to the basically same results as in Example 1. c. As a further possibility, the solution could be seeded with any polymorphic form of 2’-FL and even with amorphous 2’-FL at the stage immediately prior to the first addition of acetic acid (with relative amount comparable to those of Example 1 above) also yielding the ba- sically same results.

“Basically the same results” means that the absolute amounts of the purity of 2’-FL and the con- tents of the by-products vary to a very small extent, i.e. about less than 5% deviation from the experimental results of Example 1.

Example 2

200 g of the aqueous solution of the 2’-FL raw material (see above) was heated to 65 °C (inter nal temperature; 80 °C heating bath temperature). At a pressure of 250 mbar(abs), 38 g of wa- ter were distilled off resulting in a syrup containing 64.8 weight- % of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.5:1. The resulting syrup was expanded to ambient pressure and allowed to cool to 50 °C (bath temperature). The suspension was stirred at 50 °C (bath temperature) at ambient pressure for further 3 h and then cooled to 20 °C and stirred for further 1 h at 20 °C. Then 117 ml of acetic acid were added within 30 min while keep- ing the temperature at 20 °C, and the obtained suspension was stirred for 0.5 h at 10 °C.

The thus obtained suspension was filtered through a suction filter, and the filter cake was washed 3 times with each 15 ml of acetic acid/water (80/20 w/w) and thereafter dried at 40 °C and 0.8 mbar for 12 h. Thereby, 80.3 g (yield 75.6 %) of crystalline material having the following composition were obtained: Composition (HPLC): 0.2 % lactose, 0.3 % fucosyl lactulose and 98.8 % 2’-FL (no detectable amounts of difocusyl lactose (DiFL)).

The obtained crystalline material contained 0.015 % by weight of water as determined by Karl- Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form II, as determined by XRPD. The a:b anomeric ratio was 1.01 :1 (50.2:49:8). Crystallization directly from 50 wt-% solution w/o seeding and w/o heating yielded similar results.

The same variations as explained for Example 1 can be implemented here as well leading again to basically the same results. Example 3: Preparing seed crystals having crystalline form A (for use in Example 1 )

In a reaction flask equipped with a distillation bridge and a stirrer 200 g of the aqueous solution of the 2’-FL raw material ((0.8 wt.-% lactose; 0.4 wt.-% fucosyl lactulose; 49.4 wt.-% 2’-FI; 2.5 wt.-% DiFL water value 38.52 %) from fermentation after decolorization filtration and desalting) were heated by means of a water bath to 45 °C (bath temperature). At a pressure of 20-50 mbar(abs) about 30 g of water were distilled off resulting in a syrup containing about 58 weight- % of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.1 :1. The resulting viscous syrup was expanded to ambient pressure and seeded 45 °C (bath tempera- ture) with 0.05 g of crystalline 2’-FL obtained from Example 2 (form II). The mixture was stirred at ambient pressure and 45 °C (bath temperature) for further 16 h. The thus obtained thick sus- pension was discharged from the reactor and filtered through a heated suction filter (40 °C), and the filter cake was dried at 40 °C and 10 mbar(abs) for 16 h under a flow of inert gas. Thereby, 78.1 g of crystalline material (yield 69.3 %) having the following composition was obtained:

Composition (HPLC): 0.72 % lactose, 0.57 % fucosyl lactulose, 2.61 % DiFL and 87.64 % 2’-FL.

The obtained crystalline material contained 3.0 % by weight of water as determined by Karl- Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form A, as determined by XRPD.

The crystal structure of 2’-FL form II according to the invention was determined. The crystals show the monoclinic space group /¾. The asymmetric unit contains two molecules 2’-FL, one as a anomer and one as b anomer. Details are shown in Table 2 below. A comparison of the two molecules in the asymmetric unit is shown in Figure 2. The XRPD pattern is shown in Fig- ure 3a. A comparison between the measured XRPD pattern and the calculated XRPD pattern from single crystal structure is shown in Figure 3b. Due to thermal expansion the calculated pattern from the crystal structure determined by single crystal X-ray diffraction at 100 K is shift ed with regard to the pattern measured at room temperature. However, fitting of the unit cell dimensions leads to a good match between measured and calculated XRPD pattern.

Table 2

Crystallographic data of 2’-FL form II

data single crystal data powder data

T 100 K room temperature

crystal system monoclinic monoclinic

space group £2i P2,

a (A) 1 1 .2121 (2) 1 1.273(5)

b { A) 14.9972(3) 15.122(5)

c ( A) 12.5348(3) 12.664(6)

a (°) 90 90

b(°) 91.2907(10) 91.406(7)

(°) 90 90 i/(A ³ ) 2107.19(8) 2158.16

z 4 4

calc (g/cm ³ ) 1.540

l (A) 1.54178 1.54178

A comparison between the XRPD pattern presented in WO 2011/150939 A, in Fig. 12, and the calculated XRPD pattern from single crystal structure is shown in Figure 4. Due to thermal ex- pansion the calculated pattern from the crystal structure determined by single crystal X-ray dif fraction at 100 K is shifted with regard to the pattern measured at room temperature. However, fitting of the unit cell dimensions leads to a good match between measured and calculated XRPD pattern.

NMR-Data: The crystals of 2’-FL were dissolved and measured immediately. From the NMR data obtained, the a:b anomeric ratio can be calculated using standard means. The results are shown in Table 3 below.

Table 3

a:b anomeric ratio determined by ¹³ C-NMR spectroscopy immediately after dissolution

form a:b ratio Example

I 7.35:1 (88:12) according to Kuhn et a! 1956; Chem. Ber. 1956, page 2513

0.84 1 (46:54) Example 1 (inventive)

1 .01 1 (50.2:49.8) Example 2 (inventive)

0.14 1 (12:88) according to WO 2014/009921 A2

The NMR data of samples of the obtained 2’-FL reveal an a:b anomeric ratio of 0.84:1 , i.e.

46:54, and 1.01 :1 , i.e. 50.2:49.8.

Short description of the figures

Fig. 1 : shows the chemical structure of 2'-0-fucosyl lactose.

Fig. 2: shows that two molecules in the asymmetric unit of 2'-0-fucosyl lactose form II are two different anomers.

Fig. 3a: shows the XRPD pattern of the crystalline material obtained according to Example 1.

Fig. 3b: shows the XRPD pattern of 2'-0-fucosyl lactose form II (bottom, solid line, Example 1) in comparison to the calculated XRPD pattern of 2'-0-fucosyl lactose form II based on the crystal structure determined at 100 K (top, dashed line, mvh086) and the calculated pattern with to room temperature fitted unit cell dimensions (middle, dotted line), Cu Ka radiation. Fig. 4 : shows the XRPD pattern of 2'-0-fucosyl lactose form II (bottom, solid line, WO

201 1/150939 A Fig. 12) in comparison to the calculated XRPD pattern of inventive 2'- O-fucosyl lactose form II based on the crystal structure determined at 100 K (top, dashed line, mvh086) and the calculated pattern with to room temperature fitted unit cell dimensions (middle, dotted line), Cu-Koi,2 radiation.

Methods

M1 Determination of the a:b anomeric ratio

M1 a Determination of the a:b anomeric ratio by ¹³ C-NMR: ¹³ C-NMR measurements were carried out according to standard setup, i.e. carried out in solution“at dissolution”, i.e. only immediately after sample preparation (i.e. about 2-4 minutes after dissolution) at room temperature (i.e. about 20 °C).

M1 b Determination of the a:b anomeric ratio by ¹ H-NMR: ¹ H-NMR measurements were car- ried out according to the following setup:

Apparatus: Bruker AVN-500a

Reagents: solvent: D ₂ 0 (Euriso-top)

reference: [D ₄ ]-T rimethylsilylpropionic acid sodium salt

(3(TMS)PS-Na) (Euriso-top)

Sample preparation: The test items (approx. 20 mg => concentration = 2 g/100ml_) were weighed into 10 ml_ vials and dissolved in 1 .0 ml_ D ₂ 0 containing 3(TMS)PS-Na. The resulting solutions were trans- ferred into 5 mm NMR tubes for measurement. The measure- ments of the individual samples were started directly after prep- aration (approx. 10 min).

Test parameters: Measurement frequency = 500 MHz

Measuring temperature = 298 K

D1 = 10 s

For evaluation, the signals of the anomeric protons at C1 (alpha: 5.2 ppm, beta 4.65 ppm) were integrated and normalized:

HO

M2 Laboratory PXRD patterns were recorded with a PANalytical X ^' Pert Pro X-ray diffrac- to meter using Cu Ka radiation in reflection geometry (Bragg-Brentano). The sample was placed in a silicon single crystal sample holder of 0.2 mm depth and gently and precisely flattened. The tube voltage was 45 kV and the current was 40 mA. The PXRD data were collected at room temperature in the range from 20 =3.0°-40.0° with incre- ments of 0.017° and a measurement time of 20 s/step.

M3 Standard HPLC measurement:

HPLC: Agilent S 1200

Column: Spherisorb NH2 column (amine modified silica: particle size 3 pm, pore size 80 A) length 250 mm, internal diameter 4.5 mm (Waters Corporation) Eluent: acetonitrile/water 82.5/17.5 v/v

Detection: RID

Parameters: flow rate 1.3 ml/min, T = 35 °C, pressure 112 bar, 5 pi injection volume Quantification in weight % was based on calibration with high purity reference samples via the so called response factor

Always area % were measured and recalculated to weight % by the response factor and normalized to weight of the sample.

M3a Determination of the content of 2’-0-fucosyl lactose in a saccharide composition rela- tive to other saccharides: This determination was carried out by standard HPLC meas- urements, wherein the percentages of 2'-0-fucosyl lactose were determined relative to the total amount of other oligosaccharides in area percentages.

M3b Determination of the content of 2'-0-fucosyl lactose, relative to organic matter: This determination was carried out by standard HPLC measurement, wherein the percent- ages of 2'-0-fucosyl lactose were determined relative to the total amount of other or ganic matter detectable in HPLCL in area percentages.

M3c Determination of the content of organic solvents: This determination was carried out by standard HPLC measurements, wherein the percentages of organic solvent content were determined in area percentages; the results could be confirmed by other methods known by the skilled person.

M4 Depending on the water content, different instruments were used in the Karl Fischer measurement:

M4a General H20-% area

Metrohm 716 DMS Titrino / 703 Ti Stand Double Pt-wire electrode (6.0338.100) with Hydranal Methanol-DRY and Hydranal Composite 5 M4b hhO-ppm-in solid samples

852 Titrando + 874 Oven Sample Processor + 801 Stirrer Double Pt electrode

(6.0341.100)

Generator electrode (6.0342.110)

Hydranal Coulomat AG

M5 Determination of the ratio length dhickness of crystals: The ratio lengthdhickness of crystals was determined using the respective XRPD data according to methods and principles known by the skilled person.

M6 Determination of the characterizing features of the controlled supersaturation, c/(g/L) and c ^* /(g/L): These parameters were determined using standard methods to test solu- bilities and solubility limits such as the pharmacopeias of USA and Europe, known by the skilled person.

M7 Determination of the storage stability: This parameter was determined using standard methods to test solubilities and solubility limits such as the pharmacopeias of USA and Europe, known by the skilled person.

Method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material

Further described herein is a method for obtaining crystalline 2’-fucosyllactose from a 2’- fucosyllactose raw material, illustrated in particular by the following set of aspects and combina- tions of aspects resulting from the dependencies and back-references as indicated hereinunder. In particular, it is noted that in each instance where a range of aspects is mentioned, for exam- ple in the context of a term such as "The method of any one of aspects 1 to 4", every aspect in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The method of any one of aspects 1 , 2, 3, and 4". Further, it is explicitly noted that the following set of aspects is not the set of claims determining the extent of protection, but represents a suitably structured part of the description directed to general and preferred aspects of the method for obtaining crystalline 2’- fucosyllactose from a 2’-fucosyllactose raw material.

1. A method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material, which contains 2'-FL as a main constituent and at least 0.5% by weight, frequently at least 1 % by weight, in particular at least 2% by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligosaccharides different from 2’-fucosyllactose,

where the method comprises

a) providing a solution of the 2’-fucosyllactose raw material in water, which does not contain more than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight of organic solvents, based on the total amount of water;

b) effecting the crystallization of 2’-fucosyllactose by inducing conditions of a controlled supersaturation in the solution; and

c) separating crystalline 2’-fucosyllactose from the mother liquor;

and where during controlled supersaturation in step b) not more than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight of organic solvents are present, based on the total amount of water present during step b).

2. The method of aspect 1 , where the crystallization of 2’-fucosyllactose is effected at a tem- perature in the range from 0 to 52°C.

3. The method of aspect 1 , where the crystallization of 2’-fucosyllactose is effected at a tem- perature in the range from above 52 to 105°C.

4. The method of any one of the preceding aspects, where the conditions of a controlled su- persaturation are induced in a manner such that the ratio c : c ^* of the concentration c of dissolved 2’-fucosyllactose to the equilibrium solubility c ^* of 2’-fucosyllactose under the conditions of controlled supersaturation is from more than 1 : 1 to 1.5 : 1 , thereby effecting the crystallization of 2’-fucosyllactose.

5. The method of any one of the preceding aspects, where the controlled supersaturation is induced by removing water and/or by cooling.

6. The method of any one of the preceding aspects, where the controlled crystallization is effected in the presence of solid 2’-fucosyllactose, in particular crystalline 2’-fucosyllactose.

7. The method of any one of the preceding aspects, where the crystallization is carried out as an evaporation crystallization.

8. The method of any one of the preceding aspects, where the concentration of dissolved 2’- fu cosy I lactose under the conditions of controlled supersaturation is in the range from 400 to 750 g/L.

9. The method of any one of the preceding aspects, where the 2’-fucosyllactose raw material contains at least one oligosaccharide selected from lactose, difucosyllactose, lactulose and fucosylated lactulose.

10. The method of any one of the preceding aspects, where the solution of 2’-fucosyllactose provided in step a) does not contain more than 5000 ppm of solid insoluble material, based on the total weight of the solution.

1 1. The method of any one of the preceding aspects, where the aqueous solution of

2’-fucosyllactose provided in step a) is obtained by a fermentation process. 12. The method of any one of the preceding aspects, where the aqueous solution of

2’-fucosyllactose provided in step a) is fed to a continuously operated crystallization appa- ratus, which contains an aqueous suspension of 2’-fucosyllactose crystals.

13. The method of aspect 12, where step b) comprises

b1 ) continuously feeding the aqueous solution of 2’-fucosyllactose to a crystallization apparatus containing an aqueous suspension of 2’-fucosyllactose;

b2) continuously removing water from the aqueous suspension of 2’-fucosyllactose con- tained in the crystallization apparatus to maintain conditions of controlled supersatu- ration;

b3) continuously removing the aqueous suspension of 2’-fu cosy I lactose from the crystal- lization apparatus.

14. The method of aspect 13, where a portion of the aqueous suspension of 2’-fucosyllactose removed in step b3) is mixed with the aqueous solution of 2’-fucosyllactose of step b1 ) and the mixture is fed back it into the crystallization apparatus.

15. The method of any one of aspects 1 to 11 , where the solution of the 2’-fucosyllactose raw material is subjected to a crystallization in batch- or fed-batch operated crystallization ap- paratus.

16. The method of any of the preceding aspects, where the crystallization is carried out at a temperature in the range from 20 to 52°C in the presence of solid 2’-fucosyllactose and where the crystallization is effected from an aqueous supersaturated solution under the conditions of controlled supersaturation, where the aqueous supersaturated solution has a concentration of dissolved 2’-fucosyllactose in the range from 410 to 630 g/L.

17. The method of any of the preceding aspects, where at least a portion of the mother liquor obtained in step c) is subjected to a crystallization of 2’-fucosyllactose by inducing condi- tions of a controlled supersaturation in the mother liquor.

18. The method of aspect 17, where at least a portion of the mother liquor is mixed with the solution of the 2’-fucosyllactose raw material prior to carrying out step b).

19. The method of any one of the preceding aspects, which comprises a first crystallization step and a second crystallization step,

where the aqueous solution of the 2’-fucosyllactose raw material provided in step a) is sub- jected to a crystallization of the second crystallization step,

where in the second crystallization step the crystallization of 2’-fucosyllactose is effected by inducing conditions of a controlled supersaturation in the solution according to step b), where the aqueous suspension of the crystalline 2’-fucosyl lactose obtained in the second crystallization step is subjected to a solid-liquid separation to obtain a crystalline 2’- fucosyllactose and a mother liquor,

where the mother liquor obtained in the solid-liquid separation is introduced into the first crystallization step.

20. The method of aspect 19, where the crystalline 2’-fucosyllactose obtained in the first crys- tallization step is dissolved in the aqueous solution of the 2’-fucosyllactose raw material prior to carrying out the second crystallization step.

21. The method of any of the preceding aspects, where prior to step c) a water miscible organ- ic solvent is added to the suspension obtained in step b) when the crystallization is almost complete.

22. A method for selectively obtaining either crystalline form A or crystalline form II of

2’-fucosyllactose from a 2’-fucosyllactose raw material, which contains 2'-FL as a main constituent and at least 0.5% by weight, frequently at least 1 % by weight, in particular at least 2% by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligosaccharides different from 2’-fucosyllactose, which comprises performing the method as described in any of the preceding aspects, provided that

either the crystallization of 2’-fucosyllactose is effected at a temperature in the range from 0 to 52°C, in particular in the range from 0 to 50°C to obtain the crystalline form A or form B of 2’-fucosyllactose;

or the crystallization of 2’-fucosyllactose is effected at a temperature of above 52°C, in particular of above 53°C to obtain the crystalline form II of 2’-fucosyllactose.

2'-Fucosyllactose (CAS No.: 41263-94-9: a-L-fucopyranosyl-(1 -»2)-0-3-D-galactopyranosyl- (1- 4)-D-glucopyranose, hereinafter 2’-FL) is an oligosaccharide, which is found in relatively large quantities in breast milk. It has been variously reported that the 2'-FL present in breast milk causally reduces the risk of infection in newborns who are breast fed (see e.g. Weichert et al., Nutrition Research, 33 (2013), Volume 10, 831-838; Jantscher-Krenn et al., Minerva Pediatr. 2012, 64 (1) 83-99; Morrow et al., J. Pediatr. 145 (2004) 297-303). 2'-FL is therefore of particu- lar interest as a constituent of food supplements, particularly as additive for humanized milk products, especially for infant nutrition.

The preparation of 2'-0-fucosyl lactose by classical chemical or biochemical means has been variously described in the literature (for classic chemical means see e.g. US 5,438,124, WO 2010/070616, WO 2010/115934, WO 2010/1 15935, WO 2016/038192 and WO 2017/153452; for biochemical means see e.g. Drouillard et al. Angew. Chem. Int. Ed. 45, 1778 (2006), WO 2010/070104, WO 2012/007481 , WO 2012/097950, WO 2012/112777, WO 2013/139344, WO 2014/086373, WO 2015/188834 and WO 2016/095924).

Principally, the production of is 2’-FL by fermentation process using transformed microorgan- isms such as transformed E.coli is promising both for economic and environmental reasons. However, isolation of 2’-FL is tedious and usually requires

separating the supernatant containing the product by centrifugation, adsorption of the product on a bed of activated charcoal that was washed with water to eliminate water-soluble contaminants like salts, amino acids and protein fragments, elution of the product with alcohol or aqueous alcohol, and

last not least, separation of 2'-FL from other carbohydrates like lactose and fucose by gel permeation chromatography or flesh chromatography on charcoal celite beds.

The main drawback of this isolation method has been the need for chromatographic separation in order either to get the pure substance or to obtain at least a mixture that is enriched in the target compound but still contains undesired derivatives. Although repeated chromatographic separations can result in the improvement of the purity, its high cost and relatively long techno- logical time to handle the feed solution and the column packing, to carry out the separation and optionally to regenerate the packing, especially in large or industrial scale, can be disadvanta- geous and/or cumbersome.

Crystallization or recrystallization is principally a simple and cheap method for isolating a prod- uct from a reaction mixture and separating it from contaminations thereby obtaining a purified substance. Isolation or purification that uses crystallization may therefore render the whole technological process robust and cost-effective, thus it is principally advantageous and attrac- tive compared to other procedures. While crystallization of 2’-FL, which has been prepared by classical organic synthesis, is an efficient means for isolation or purification of 2’-FL, crystalliza- tion cannot be easily applied to 2’-FL, which has been prepared by non-classical organic syn- thesis, because the product obtained by fermentative production of 2'-FL contains a significant amount of by products, including in particular oligosaccharides other than 2’-FL, but also mono- saccharides. As these mono- and oligosaccharides have comparable polarities and, hence, comparable solubilities, they are difficult to separate by crystallization processes.

Kuhn et al. (Chem. Ber. 1956, page 2513) report that 2’-FL which has been purified by repeated chromatography does not readily crystallize but remains a syrup. The authors mention that few crystals of 2’-FI formed when leaving an aqueous solution of 2’-FL standing for a prolonged pe- riod. Larger amounts of crystalline 2’-FL could be obtained only from solutions containing mix- tures of water with a considerable amount of organic solvents.

WO 2014/086373 describes a method for obtaining an oligosaccharide such as 2’-FL from a fermentation broth, which comprises freeze-drying of the fermentation broth, preferably after having removed proteins therefrom, to produce a dry powder, treating the dry powder with an aliphatic alcohol, such as methanol, to dissolve the oligosaccharide which is then crystallized from the alcoholic solution. The method is tedious as it requires previous freeze drying of the fermentation broth and the use of organic solvents.

WO 2015/188834 describes a method for crystallization of 2’-FL from an aqueous solution con- taining 2’-FL and a fucosylated oligosaccharide, such as difucosyllactose, which method corn- prises fermentative production of 2’-FL by using genetically modified cells having a recombinant gene that encodes a 1 ,2-fucosyltransferase, separating the supernatant from non-carbohydrate solids and contaminants and adding Ci-C4-alkanols in order to effect crystallization of 2’-FL.

WO 2016/188834 describes a method for crystallization of 2’-FL from an aqueous solution con- taining 2’-FL and a fucosylated oligosaccharide, such as difucosyllactose, which method corn- prises providing an aqueous solution of 2’-FL and the fucosylated oligosaccharide as described in WO 2015/188834 and addition of acetic acid to the aqueous solution in order to effect crystal- lization of 2’-FL.

WO 2014/009921 describes different polymorph forms of 2’-FL. While polymorph form B can be obtained by recrystallization of pure 2’-FL, e.g. pure polymorph form A, from water, purification of a 2’-FL containing raw material, which additionally contains considerable amounts of mono- or oligosaccharides different from 2’-FL is not described therein.

WO 2018/164937 describes a process for crystallizing 2’-FL from an aqueous solution, which requires precipitating 2’-FL from an aqueous supersaturated solution at a temperature of greater than 60°C. By this method, the crystalline anhydrate of 2-FL, i.e. form II of 2’-FL, is obtained, which is described in WO 201 1/150939.

The methods for obtaining crystalline still require considerable amounts of organic solvents dur- ing crystallization, which are difficult to remove, as they are frequently entrapped in the crystal- line material. Especially for baby and the use of organic solvents is not acceptable, as it always bears the risk that the organic solvent cannot be completely removed.

There is still a need for an efficient process for obtaining crystalline 2'-FL from a 2'-FL raw mate- rial, which contains considerable amounts of mono- and oligosaccharides other than 2'-FL, such as lactose, acetyl ated 2'-FL, fucosylated lactose other than 2’-FL, and fucosylated lactulose, from aqueous solution of such raw materials, in in particular form aqueous solutions obtained by a fermentation process. The method should in particular allow the avoidance of organic solvents and provide 2'-FL in high purity and high yield.

It has been found that 2'-FL can be efficiently and reliably crystallized from an aqueous solution of a 2'-FL raw material, which contains considerable amounts of mono- and oligosaccharides other than 2'-FL, by inducing conditions of controlled supersaturation in the aqueous solution and thereby effecting selective crystallization of 2'-FL. Inducing conditions of controlled super- saturation in the aqueous solution of 2'-FL raw material allows for efficient crystallization without the use of considerable amounts of organic solvents during crystallization. This is quite surpris- ing, because 2'-FL is highly soluble in water and even pure 2’-FL hardly crystallizes from water and the considerable amounts of mono- and oligosaccharides contained in the 2'-FL raw mate- rial should further hamper crystallization of 2’-FL.

Therefore, described herein is a method for obtaining crystalline 2’-fucosyllactose from a 2'-FL raw material, which contains 2'-FL as a main constituent and at least 0.5% by weight, frequently at least 1 % by weight, in particular at least 2% by weight, more particularly at least 5% by weight, and especially at least 8% by weight, based on the total amount of mono- and oligosac- charides in the raw material, of one or more mono- or oligosaccharides different from 2’-FL, where the method comprises

a) providing a solution of the 2'-FL raw material in water, which does not contain more than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight of organic solvents, based on the total amount of water;

b) effecting the crystallization of 2’-FL from the solution provided in step a) by inducing condi- tions of a controlled supersaturation in the solution at a temperature of preferably at most 60°C; and

c) separating crystalline 2'-FL from the mother liquor,

and where during controlled supersaturation in step b) not more than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight of organic solvents are present, based on the total amount of water present during step b).

This method is associated with several benefits. It allows efficient separation of 2’-FL from the other oligosaccharides, thereby obtaining 2’-FL in high yield and high purity of frequently more than 93%, in particular more than 95%, especially at least 97% or at least 98%, based on or ganic matter in the crystalline 2’-FL. In particular, the method does not require the use of organ- ic solvents during crystallization and, therefore, the risk that the crystalline 2’-FL contains signif- icant amounts of entrapped organic solvent is minimized. The process results in a mother liquor, which is colorless or almost colorless and thus can be subjected to further crystallization steps or re-introduced into the solution to be crystallized prior to effecting the crystallization.

By the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material, pure crystalline 2’-FL is obtained in the form of compact crystals.

Surprisingly, the method allows for selective crystallization of two polymorphic forms of 2'-FL in a reliable manner, namely

the anhydrate form II, which is described in WO 2011/150939 and which can be identified, e.g. by its characteristic reflections in an X-ray powder diffractogram, in particular the fol- lowing reflections, quoted as 20 values: 16.98 ± 0.2°, 13.65 ± 0.2° and 18.32 + 0.2°, (at 25°C and Cu-Ka radiation);

the hydrate form A, which is described in WO 2014/009921 and which can be identified, e.g. by its characteristic reflections in an X-ray powder diffractogram, in particular the fol- lowing reflections, quoted as 20 values: 18.86 ± 0.2°, 17.05 ± 0.2° and 9.89 + 0.2°, (at 25°C and Cu-Ka radiation); or

the hydrate form B, which is described in WO 2014/009921 and which can be identified, e.g. by its characteristic reflections in an X-ray powder diffractogram, in particular the fol- lowing reflections, quoted as 20 values: 20.48 ± 0.2°, 1 1.90 ± 0.2° and 9.96 ± 0.2°, (at 25°C and Cu-Ka radiation). This is of particular importance for the registration of 2’-FL, which may require the reliable pro- duction of a specific polymorph form. The method allows for the selective preparation of either the crystalline an hydrate form II or the crystalline hydrate forms A or B of 2’-FL depending on the temperature at which the crystallization of 2’-FL is effected. In particular, the hydrate forms A or B will be obtained, if the crystallization of 2’-FL is effected at a temperature of at most 52°C, in particular at most 50°C, more particularly at most 48°C and especially at most 45°C, e.g. in the range from 0 to 52°C, in particular from 0 to 50°C, more particularly from 0 to 48°C and especially from 0 to 45°C, while the an hydrate form II will be obtained, if the crystallization of 2’-FL is effected at a temperature of above 52°C in particular at a temperature of above 53°C. It is noted that the crystalline hydrate form B is initially formed, when effecting crystallization at a temperature of at most 52°C, in particular at most 50°C, more particularly at most 48°C and especially at most 45°C. The crystalline hydrate form B, however, will convert into the crystalline hydrate form A upon drying.

Therefore, described herein is a method for selectively obtaining either the crystalline hydrate forms A or B of 2’-FL or the crystalline an hydrate form II of 2’-FL from a 2’-FL raw material as defined herein, which method comprises performing the method for obtaining crystalline 2’-FL as described herein, provided that

either the crystallization of 2’-fucosyllactose is effected at a temperature in the range from 0°C to 52°C, in particular from 0 to 50°C, more particularly from 0 to 48°C and especially from 0 to 45°C to obtain the crystalline forms A or B of 2’-fucosyllactose

or the crystallization of 2’-fucosyllactose is effected at a temperature of above 52°C, in par- ticular of at least or above 53°C and preferably at most 60°C to obtain the crystalline form II of 2’-fucosyllactose.

Here and in the following the terms 2’-FL and 2'-fucosyl lactose are used synonymously and refer to a-L-fucopyranosyl-(1 >2)-0-3-D-galactopyranosyl-(1- 4)-D-glucopyranose, including the a- and b-anomers and mixtures thereof.

The term“2’-FL raw material” as used herein refers to an oligosaccharide composition, which contains 2'-FL as a main constituent, in particular in an amount of at least 70% by weight, and a considerable amount, i.e. at least 0.5% by weight, frequently at least 1 % by weight, in particular at least 2% by weight, more particularly at least 5% by weight, and especially at least 8% by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligosaccharides different from 2’-fucosyllactose. In particular, the 2’-FL raw ma terial from which crystalline 2’-FL is obtained by the method for obtaining crystalline 2’- fucosyllactose from a 2’-fucosyllactose raw material contains:

70 to 99.5% by weight, in particular 75 to 95% by weight, especially 78 to 92% by weight, based on the total amount of mono- and oligosaccharides in the raw material, of 2'-FL, and 0.5 to 30% by weight, in particular 5 to 25% by weight, especially 8 to 22% by weight, based on the total amount of mono- and oligosaccharides in the raw material, of one or more mono- or oligosaccharides different from 2’-fucosyllactose. Typical mono- and oligosaccharides contained in the 2’-FL raw material, which are different from 2’-fucosyllactose, include but are not limited to lactose, fucosylated lactose other than 2’- FL, fucose, galactose, glucose, lactulose and fucosylated lactulose. These mono- and oligosac- charides are hereinafter termed“carbohydrate impurities or byproducts”.

The term“fucosylated lactose other than 2’-FL” as used herein includes any monofucosylated lactose other than 2’-FL. The term“fucosylated lactose other than 2’-FL” also includes any poly- fucosylated lactose, in particular a difucosylated lactose which is also termed“difucosyllactose”, such as 2,2’-0-difucosyllactose or 2’,3-O-difucosyllactose.

Likewise, the term“fucosylated lactulose” used herein includes any monofucosylated lactulose and polyfucosylated lactulose, i.e. lactulose, which is fucosylated on the galactose moiety of lactulose by 1 or more, e.g. 1 or 2 fucose moieties.

The aforementioned carbohydrate impurities or byproducts may be formed during fermentation or under post-fermentation conditions. For example, fucosylated lactose other than 2’-FL may be formed as a result of a deficient, defective or impaired fucosylation other than an a-1 ,2- fucosylation on the galactose moiety of lactose, or of a fucose migration of 2’-FL under the fer- mentation or post-fermentation conditions or of fucose hydrolysis from multi-fucosylated lactose. Other carbohydrate impurities or byproducts may be formed by rearrangement such as lactu- lose and fucosylated lactulose or by hydrolysis such as fucose, glucose, galactose and lactose or may be unconsumed starting material, such as glucose or lactose.

In particular, the 2’-FL raw material contains at least one fucosylated lactose other than 2’-FL, in particular difucosyllactose. In particular, the amount of fucosylated lactose is in the range from 0.3 to 10% by weight, in particular 0.5 to 10% by weight, especially 1 to 10% by weight, based on the weight of mono- and oligosaccharides contained in the 2’-FL raw material. In particular, the 2’-FL raw material also contains at least one of lactulose and fucosylated lactulose or a mix- ture of both. In particular, the total amount of lactulose and fucosylated lactulose is in the range from 0.2 to 10% by weight, in particular 0.5 to 10% by weight, especially 1 to 10% by weight, based on the weight of mono- and oligosaccharides contained in the 2’-FL raw material.

In a first step a) of the above-described method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material, an aqueous solution of 2’-FL raw material is provided which is then subjected to a crystallization in the second step b) under conditions of controlled supersat- u ration. Principally, any aqueous solution of 2’-FL raw material, which does not contain more than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight of organic solvents, based on the amount of water contained therein, can be utilized in the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material.

It is essential for said method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material that the aqueous solution of the 2’-FL raw material provided in step a) and which is subjected to the crystallization in step b) and also the water present during step b) does not contain considerable amounts of organic solvents. Accordingly, the concentration of organic solvents in the solution provided in step a) does not exceed 5% by weight, in particular not ex- ceed 2% and especially not exceed 1 % by weight, based on the water contained in the solution provided in step a). Furthermore, the concentration of organic solvents in the water which is present during step b) does not exceed 10% by weight, preferably not exceed 7% by weight, more preferably not exceed 5% by weight, in particular not exceed 2% and especially not ex ceed 1 % by weight, based on the water present during step b). In this context, the term“organic solvent” includes any organic compound, which has a boiling point at normal pressure in the range from 30 to 250°C and includes, e.g. organic alcohols, in particular CrC ₄ -alkanols and Cr C ₄ -alkanoic acids and any other organic compounds commonly used in the field of organic chemistry, in particular in the field of carbohydrate chemistry.

The aqueous solution may be an aqueous solution obtained from a biochemical process or from a conventional, i.e. chemical process.

The aqueous solution of the 2’FL raw material utilized in the method for obtaining crystalline 2’- fucosyllactose from a 2’-fucosyllactose raw material is preferably obtained from a biochemical process, such as a process, where 2’-FL is obtained by an enzymatic biocatalytic fucosylation of lactose or by a fermentation, as described e.g. in Drouillard et al. Angew. Chem. Int. Ed. 45, 1778 (2006), WO 2010/070104, WO 2012/007481 , WO 2012/097950, WO 2012/112777, WO 2013/139344, WO 2014/086373, WO 2015/188834 and WO 2016/095924.

The fermentation broth usually contains in the supernatant of the culture medium at least 25 g/L of 2’-FL and may contain up to 120 g/L of 2’-FL or even more than 120 g/L of 2’-FL. In addition, the supernatant may also contain DFL, typically in amounts of about 1.5 to 20% by weight, rela- tive to 2'-FL. The 2'-FL/DFL-mixture optionally contains fucosylated lactulose, which is produced in the culture medium, and/or lactose as unconsumed acceptor or further mono- or oligosaccha- rides.

If the aqueous solution of the raw material utilized in the method for obtaining crystalline 2’- fucosyllactose from a 2’-fucosyllactose raw material is obtained from a biochemical process, in particular from a fermentation, the obtained aqueous solution is frequently subjected to a post treatment prior to crystallization.

Such a post treatment may comprise a conventional demineralization step during which miner- als, salts and other charged molecules are extracted from the aqueous solution before crystal I i- zation. The demineralization can be conducted by using conventional ion exchange resins, namely passing the aqueous solution through a cation exchange resin in H ⁺ -form and an anion exchange resin in free base form. The cation exchange resin is preferably a strong exchanger, and the anion exchange resin is preferably a weak exchanger. The ion exchange resins, be- sides removing salts and charged molecules from the solution, can physically adsorb proteins, DNA and colorizing/caramel bodies that optionally left in the solution after previous purification steps. Alternatively, the demineralization can be conducted by means of a conventional electro- dialysis. Additionally, adsorbents such as activated carbon may be optionally employed to re- move colorizing compounds from the aqueous solution.

In some cases, it may be desirable to selectively remove some components of the aqueous solution of 2’-FL before crystallization. This may be achieved using different types of chromatog- raphy such as elution chromatography with or without a recycle loop or with continuous chroma- tographic processes such as simulated moving bed chromatography (SMB) including the varia- tions thereof with asynchronous switching of the inlets and the outlets and/or variations of flow rates and/or feed concentration during a switch interval. Methods for using SMB for purification of aqueous solutions of oligosaccharides, such as 2’-FL, obtained from a fermentation have been described e.g. by T. Eiwegger et al., Pediatric Research, Vol. 56 (2004), pp. 536 - 540,

CN 102676604 and EP 2857410, which can be applied by analogy for removing some compo- nents of the aqueous solution of 2’-FL before crystallization. A review of suitable methods for performing SMB can be found in M. Ottens et al.,“Advances in process chromatography and application”, Chapter 4.4.3, pp. 132 - 135, Woodhead Publishing Limited 2010 and the literature cited therein.

The solution obtained by any above ways can then be concentrated by either a conventional evaporation step or a conventional nanofiltration step, including ultrafiltration and diafiltration. Also, a microfiltration may be incorporated to remove proteins and macromolecules. A further final (“sterile”) filtration before crystallization may be included to remove microbial contaminants.

It has been found beneficial, if the aqueous solution of 2'-FL raw material, which is provided in step a), is essentially free of water-insoluble solid material, i.e. the amount of water-insoluble material is less than 5000 ppm, in particular less than 1000 ppm, based on the 2’-FL contained therein, or at most 3000 ppm, in particular at most 1000 ppm, based on the weight of the aque- ous solution of the 2’-FL raw material. Therefore, post treatment will preferably comprise a con- ventional clarification step. By this clarification step, cells fragments (debris) and proteins after fermentation are removed. Clarification is preferably prior to the charcoal treatment described below. The clarification can be done in a conventional manner, e.g. by sedimentation in centri- fuge producing a clarified or partially clarified supernatant solution. Alternatively, the fermenta- tion broth can be subjected to filtration step, e.g. to a micro-filtration or ultrafiltration, prior to subjecting it to the crystallization of step b). For example, ultrafiltration is performed in a conven- tional manner and removes high molecular weight components. The semipermeable membrane used for ultrafiltrating a 2'-FL fermentation broth can suitably have a cut-off of 5-50 kDa, prefer- ably 10-25 kDa, more preferably around 15 kDa. Depending on the characteristics of the fer- mentation broth to be clarified, a combination of higher and lower cut off-membranes (in this order) within the above given range may be employed. Optionally, centrifugation or ultrafiltration can be followed by nanofiltration, during which the aqueous solution containing 2'-FL and car- bohydrate by-products is concentrated in a conventional manner before it is treated with char- coal. In this nanofiltration step, its membrane can have a pore size that ensures retention of 2'- FL having a molecular weight of 488; so, typically, a 200-300 Da cut off membrane can be used. In addition, post-treatment can further comprise a conventional charcoal treatment, which is preferably conducted before the demineralization step, in order to remove color bodies and op- tionally water-soluble bio-junk optionally left from previous purification steps. The carbohydrate compounds have strong affinity to be adsorbed on charcoal in aqueous medium; thus, water- soluble contaminants can be easily washed away with (distilled, preferably food-grade) water. The carbohydrates can then be eluted from the charcoal bed with alcohol or aqueous alcohol.

In step b) the crystallization of 2’-FL is effected by inducing conditions of a controlled supersatu- ration in the solution the 2’-FL raw material.

The concentration of 2’-FL in the aqueous solution, which is subjected to crystallization in step b), may generally vary from 400 to 750 g/L or from 500 to 750 g/L, in particular in the range from 500 to 700 g/L depending on the temperature of the aqueous solution. Frequently, the total con- centration of carbohydrates, i.e. 2’-FL and mono- and oligosaccharides different from 2’-FL is in the range from 510 to 950 g/L, in particular in the range from 510 to 850 g/L.

Frequently, a dilute solution having a concentration of 2’-FL of at most 500 g/L, in particular at most 450 g/L, especially at most 400 g/L, e.g. in the range from 25 to 450 g/L or in the range from 50 to 400 g/L is provided in step a), which is then subjected to a concentration step, e.g. by evaporation of water, to a concentration of 2’-FL, where crystallization may occur, which is in particular in the range from 400 to 750 g/L or from 500 to 750 g/L, in particular from 420 to 720 g/L or from 510 to 720 g/L.

The concentration of the dilute solution to the desired concentration range for crystallization and the crystallization may be conducted in a single step, i.e. in the crystallization apparatus. It is also possible to perform a pre-concentration step first, where water is removed by evaporation, until a concentration 2’-FL is achieved, which is still below the solubility of 2’-FL under the equi- librium conditions. Then, this solution is introduced into the crystallization apparatus and in the thus concentrated solution conditions of controlled supersaturation are induced. The concentra- tion of 2’-FL which corresponds to the solubility under conditions of equilibrium is also termed the equilibrium concentration or equilibrium solubility c ^* under the given conditions. As men- tioned above, the concentration of 2’-FL in the solution, where conditions of controlled super- saturation are induced are typically in the range from 400 to 750 g/L, in particular in the range from 410 to 700 g/L or in the range from 410 to 650 g/L.

For the purpose of the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material, it has been found beneficial, if the concentration of 2’-FL in the aqueous solution of the 2’-FL raw material, which is subjected to crystallization in step b), does not exceed 650 g/L, in particular 630 g/L and is e.g. in the range from 400 to 650 g/L or from 500 to 650 g/L, in particular from 410 to 630 g/L or from 500 to 630 g/L and especially from 510 to 630 g/L. it is, however, also possible to subject an aqueous solution of the 2’-FL raw material to the crystallization in step b), which has a concentrations of 2’-FL of above 630 g/L, in particular above 650 g/L.

Inducing conditions of controlled supersaturation at the given conditions ensures that the de- si red polymorph can be selectively crystallized from the aqueous solution of the 2’-FL raw mate- rial.

Controlled supersaturation means that during crystallization the degree of supersaturation does not exceed a value, where uncontrolled, i.e. spontaneous crystallization does occur. The degree of supersaturation is understood as the ratio of the actual concentration c of dissolved 2’-FL during crystallization to the equilibrium solubility c ^* of 2’-FL in water at the given conditions, i.e. the ratio c : c ^* . In particular the ratio c : c ^* will not exceed a value of 1.5 : 1 , in particular a value of 1 .3 : 1 , more particular a value of 1.2 : 1 , especially a value of 1 .15 : 1. Apparently, supersat- u rati on requires that the ratio c : c ^* exceeds the state of the thermodynamic equilibrium, i.e. the state where the ratio c : c ^* is 1 , i.e. that c : c ^* has a value of more than 1 : 1 . The value of more than 1 : 1 indicates e.g. a value of 1 .00001 : 1 , 1 .0005 : 1 , 1 .0001 : 1 , 1.0005 : 1 , 1.001 : 1 or 1 .0002 : 1 , in particular a value in the range of 1 .00001 to 1 .002 : 1 . The equilibrium concentra- tion c ^* of 2’-FL in water at a given temperature or pressure is known or can be determined by routine experiments. The actual concentration of dissolved 2’-FL in water can be calculated uti lizing the concentration of 2’-FL in the aqueous solution, the amount of 2’-FL fed to the crystalli zation apparatus, the amount of water removed and the amount of crystallized 2’-FL. The actual concentration of the solution or suspension may also be determined experimentally, e.g. by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) or by density measurement.

The concentration of dissolved 2’-FL and thus the degree of supersaturation is usually adjusted by removing water from the aqueous solution of the 2’-FL raw material, i.e. by increasing the concentration of 2’-FL under conditions of the crystallization, and/or by cooling, i.e. by decreas- ing the solubility of 2’-FL under conditions of crystallization, and in particular by evaporation or by a combination of both.

For achieving or maintaining conditions of supersaturation, water is preferably removed by evaporation. In particular, conditions of supersaturation are induced and maintained by evapo- ration of water or by combined evaporation/cooling. In other words, the crystallization is prefer- ably carried out as an evaporation crystallization i.e. the concentration of 2’-FL in the reaction vessel is increased under conditions of the crystallization by evaporation of water, which may of course be accompanied by cooling or where after evaporation of water the initially obtained aqueous suspension of the crystalline 2’-FL is cooled to increase the yield of crystallized 2’-FL.

Preferably, water is removed by evaporation under reduced pressure. Preferably, water is evaporated at pressures in the range from 10 to 900 mbar, in particular in the range from 50 to 800 mbar. Preferably, evaporation is performed at a temperature of at least 20°C, in particular at least 25°C, more particularly at least 30°C, especially at least 35°C. Generally, the temperature will not exceed 105°C, in particular not exceed 100°C or 95°C. In particular, the evaporation tem- perature will not exceed 62°C or 60°C. The temperature, where evaporation is performed, will also depend on the type of polymorph produced. If it is desired to obtain polymorph A or poly- morph B, the aqueous solution is usually concentrated at a temperature in the range from 20 to below 52°C, in particular in the range from 25 to 50°C, more particularly from 30 to 48°C, espe- cially from 35 to 45°C while for obtaining the anhydrate form II the aqueous solution of the 2’-FL raw material is usually concentrated at a temperature in the range from above 52 to 105°C, fre- quently from 52 to 100°C or from 52 to 95°C, in particular from 52 to 65°C or from 52 to 60°C.

Evaporation of water may be achieved by conventional means using any equipment which al- lows for removal of water by distillation. The type of apparatus will depend in a known manner from whether water is removed during pre-concentration or for inducing conditions of controlled supersaturation and also whether the crystallization is operated discontinuously, i.e. batch or semi-batch, or continuously.

For inducing conditions of supersaturation by evaporation of water in a batch or semi-batch op- erated crystallization a simple vessel may be used, where the necessary heat is transferred by a heating device, e.g. by a double jacket, by heating elements in the vessel, by an external pumping loop with a heat exchanger or by a combination of these apparatuses. If the crystalliza- tion is performed in a continuous manner, a continuously operating crystallization apparatus will be used for inducing conditions of supersaturation by evaporation of water, such as stirred tank vessels, stirred tank vessels with guiding pipe, forced circulation crystallizers (FC), draft tube baffle crystallizers (DTB) or Oslo crystallizers. The evaporators may be heated with convention- al heating media such as heating oils or heating steam, including steam from a steam network or steam provided in the method for obtaining crystalline 2’-fucosyllactose from a 2’- fucosyllactose raw material by vapor recompression.

Evaporation of water in the pre-concentration step may be achieved by conventional means using any equipment which allows for removal of water by distillation, such stirred tank vessels, thin film evaporators, falling film evaporator and helical tube evaporators. Preferably, evapora- tion of water in the pre-concentration step is achieved by means of a falling-film evaporator, preferably using heating steam obtained by mechanical vapor recompression. Mechanical vapor recompression allows for reducing the required amount of fresh steam, thereby reducing the overall costs. Vapor recompression is preferably achieved by one or more rotary compressors. Because of the moderate compression stroke of the vapor recompression and thus the limited temperature raise at the heating section falling film evaporators are preferably used, as they can be operated at a small temperature gradient. The falling film evaporator allows for a high evapo- ration rate at small circulation rates and low pressure drops. Thus, falling film evaporators allow for short residence times of the temperature sensible 2'-FL. Moreover the low pressure drop of falling film evaporators is beneficial for vapor recompression and thus for heat recovery. It is beneficial to connect several evaporators in series, because this allows for keeping the temper ature difference between heating side and process side high, thereby allowing for small surfac- es in the heat exchanger.

The amount of water removed is usually chosen such that at least at the beginning of the crys- tallization the concentration of dissolved 2’-FL in the aqueous medium present in the crystal I iza- tion is in the range as given above and thus may vary from 400 to 750 g/L or from 500 to 750 g/L and in particular from 410 to 720 g/L or from 510 to 720 g/L, depending on the temperature during crystallization. As explained above, a concentration of dissolved 2’-FL of at most 650 g/L, in particular at most 630 g/L, e.g. in the range from 400 to 650 g/L and especially from 410 to 630 g/L, in the aqueous medium present during crystallization may be beneficial. However, con- centrations of 2’-FL of above 630 g/L, in particular above 650 g/L in the aqueous medium p re- sent during crystallization may also be possible. It is also apparent that in a continuously oper- ated crystallization the concentration of dissolved 2’-FL in the water present during crystal I iza- tion is in the ranges given here throughout the crystallization.

For effecting crystallization, the controlled supersaturation is typically induced at a temperature of at least 0°C, in particular at least 10°C or at least 20°C. The temperature, where the con- trolled supersaturation is induced, will typically not exceed 105°C in particular not exceed 100°C more particularly not exceed 95°C or 90°C, especially not exceed 85°C. In order to avoid dis- coloration, the temperature will preferably not exceed 60°C and is in particular below 60°C.

If controlled supersaturation is induced by a process which includes evaporation of water, here- inafter referred to as evaporation crystallization, the temperature where supersaturation is in- duced is typically at least 20°C, in particular at least 25°C, especially at least 30°C or at least 35°C. Generally, the temperature will not exceed 105°C, in particular not exceed 100°C more particularly not exceed 95°C or 90°C, especially not exceed 85°C. In order to avoid discoloration of the mother liquor the crystallization temperature will preferably not exceed 60°C and is in particular below 60°C. In particular the supersaturation is induced at a temperature in the range from 0 to 95°C or in the range from 0 to 60°C, more particularly in the range from 0 to 90°C or in the range from 0 to below 60°C, especially in the range from 0 to 85°C or in the range from 0 to 58°C. If controlled supersaturation is induced by evaporation crystallization, the supersatura- tion is preferably induced at a temperature in the range from 25 to 95°C or in the range from 25 to 60°C, more preferably in the range from 30 to 90°C or in the range from 30 to below 60°C and especially in the range from 35 to 85°C or in the range from 35 to 58°C.

If it is intended to produce polymorph B or A, respectively, by evaporation crystallization, the supersaturation is typically induced at a temperature in the range from 20 to 52°C, in particular in the range from 25 to 50°C, more particularly in the range from 30 to 48°C especially in the range from 35 to 45°C. For production of the hydrate form II supersaturation is typically induced at a temperature in the range from above 52 to 105°C, in particular in the range from 52 to 100°C, especially in the range from 52 to 95°C or from 52 to 90°C or from 52 to 85°C or from 52 to 60°C or from 52 to below 60°C or from 52 to 58°C. If controlled supersaturation is induced by a process which does not include evaporation of wa- ter, e. g. where the temperature where supersaturation is induced by cooling, the temperature may be lower than the above given ranges and may be as low as 0°C. In this case the tempera- ture, where crystallization is induced, is typically in the range from 0 to 60°C, in particular in the range from 0 to below 60°C, or in the range from 0 to 58°C. The temperature will of course de- pend on the desired polymorph form of 2’-FL.

The crystallization of 2’-FL is usually performed at ambient pressure or under reduced pressure, e.g. at a pressure in the range from 10 to 1020 mbar. The pressure will of course depend on the temperature and the concentration of the aqueous solution of the 2’-FL raw material. It may be beneficial to perform the crystallization of 2’-FL at reduced pressure in order to facilitate removal of water by evaporation during crystallization. Then, crystallization of 2’-FL is preferably carried out at a pressure in the range from 10 to 900 mbar, in particular from 20 to 800 mbar and espe- cially from 30 to 700 mbar.

During crystallization the temperature may be further reduced and/or water may be further evaporated in order to drive crystallization to completion, in particular, if crystallization is per formed batch-wise or in semi-batch procedures. Of course, the temperature will be in the above ranges, if crystallization of 2-FL’ is performed continuously.

In order to achieve a control of supersaturation, measures are taken which favor crystallization and prevent kinetic inhibition of crystallization and thus excess oversaturation. Such measures are in particular performing the crystallization in the presence of solids, such as amorphous 2’- FL or in particular crystalline 2’-FL. Other solids may also be used, including solid CO2. It may also be possible to apply ultrasound in order to prevent kinetic inhibition of the crystallization. Of course measures which favor crystallization will be taken in particular, when the ratio c : c ^* does not exceed a value of 1.5 : 1 , in particular not exceed a value of 1.3 : 1 , more particular not ex- ceed a value of 1.2 : 1 , especially not exceed a value of 1.15 : 1.

According to one aspect of the method for obtaining crystalline 2’-fucosyllactose from a 2’- fucosyllactose raw material, seed crystals of 2’-FL are added, preferably but not necessarily seed crystals of the desired polymorph form. This measure is in particular taken, if the crystalli zation is conducted in a discontinuous manner. Then the amount of seed crystals will usually be in the range from 0.01 to 5% by weight, in particular in the range from 0.02 to 3% by weight or 0.02 to 1 % by weight, with respect to pure 2’-FL in the aqueous solution subjected to crystalli zation in step b).

In order to perform the crystallization in the presence of crystalline 2’-FL, it is also possible to feed the aqueous solution to a suspension of crystalline 2’-FL in water under conditions of con- trolled supersaturation. In the aqueous suspension, the solid content is preferably in the range from 5 to 60% by weight, in particular from 10 to 45% by weight and especially from 20 to 40% by weight, based on the total weight of the suspension. Preferably, the concentration of dis- solved 2’-FL in the aqueous phase of the suspension of 2’-FL under the conditions of supersatu- ration is preferably in the range from 400 to 750 g/L or from 500 to 750 g/L, in particular from 410 to 720 g/L or from 510 to 720 g/L, more particularly in the range from 400 to 650 g/L and especially from 410 to 630 g/L, depending on the temperature during crystallization and de- pending on which polymorph form is desired.

In a very preferred group of aspects, the crystallization of step b) is carried out at a temperature in the range from 20 the 52°C, in particular in the range from 25 to 50°C, more particular in the range from 30 to 48°C and especially in the range from 35 to 45 °C in the presence of solid 2’- fucosyllactose, in particular crystalline 2’-fucosyllactose, and where the crystallization is effected from an aqueous supersaturated solution under the conditions of controlled supersaturation as described herein, where the aqueous supersaturated solution has a concentration of dissolved 2’-fucosyllactose at least initially in the range from 410 to 630 g/L.

The crystallization of 2’-FL can be performed in any type of crystallization apparatus which can be utilized for a crystallization of an organic compound from an aqueous solution. Suitable crys- tallization apparatus include but are not limited to stirred tank crystallizers, stirred tank crystal- lizers with guiding pipe, stirred tank crystallizers with guiding pipe and optionally with means for classification of the crystals, so called draft tube crystallizers or draft tube baffle (DTB) crystal- lizers, forced circulation crystallizers optionally having means for crystal classification, such as Oslo-type crystallizers, induced forced circulation crystallizers optionally having means for crys- tal classification, and cooling-plate crystallizers. Preferred crystallizers are selected from the group of forced circulation crystallizers, draft tube crystallizers, draft tube baffled crystallizers, Oslo-type crystallizers and induced forced circulation crystallizers, with particular preference given to draft tube baffled crystallizers and induced forced circulation crystallizers.

As pointed out above, the method for obtaining crystalline 2’-fucosyllactose from a 2’- fucosyllactose raw material can be performed discontinuously, i.e. batch-wise, or as a semi- batch or continuously.

Batch-wise means that the aqueous solution of the 2’-FL raw material is charged to a crystalli- zation vessel and conditions of controlled supersaturation are induced therein in order to effect crystallization of 2’-FL. Thereby 2’-FL is depleted from the solution and thus the concentration of 2’-FL decreases. In order to prevent kinetic inhibition of crystallization, solid matter, in particular amorphous or crystalline 2’-fucosyl lactose and especially seed crystals of 2’-FL are preferably added. In order to maintain conditions of controlled supersaturation, water may be evaporated during crystallization or the temperature may be decreased during crystallization or both measures are taken. In particular solid matter, in particular amorphous or crystalline 2’- fucosyllactose and especially seed crystals of 2’-FL are added, when the ratio c : c ^* does not exceed a value of 1.5 : 1 , in particular not exceed a value of 1.3 : 1 , more particular not exceed a value of 1.2 : 1 , especially not exceed a value of 1.15 : 1. Usually, the obtained aqueous sus- pension of the crystalline 2’-fucosyllactose is discharged from the crystallization vessel and sub- jected to a solid-liquid separation step, when the desired amount of 2’-fucosyl lactose has been crystallized from the solution. Frequently, the batch-wise crystallization is carried out such that the suspension finally contains the solid crystalline 2’-FL in an amount from 5 to 55% by weight, in particular from 10 to 45%, especially 20 to 40% by weight, based on the weight of the sus- pension.

Semi-batch means that a portion of the aqueous solution of the 2’-FL raw material is charged to a crystallization vessel and conditions of controlled supersaturation are induced therein in order to effect crystallization of 2’-FL. In order to prevent kinetic inhibition of crystallization, solid mat- ter, in particular amorphous or crystalline 2’-fucosyllactose and especially seed crystals of 2’-FL are preferably added. Then, further amounts of the aqueous solution of the 2’-FL raw material are fed to the crystallization apparatus and thus to the aqueous suspension of partially or com- pletely crystallized 2’-FL. In order to maintain conditions of controlled supersaturation, water may be evaporated during crystallization or the temperature may be decreased during crystalli zation or both measures are taken. Usually, the obtained aqueous suspension of the crystalline 2’-fucosyllactose is discharged from the crystallization vessel and subjected to a solid-liquid separation step, when the desired amount of 2’-fucosyl lactose has been crystallized from the solution. Frequently, the semi-batch-wise crystallization is carried out such that the suspension finally contains the solid crystalline 2’-FL in an amount from 5 to 55% by weight, in particular from 10 to 45%, especially 20 to 40% by weight, based on the weight of the suspension.

In another group of aspects, the crystallization is performed continuously. For this, the aqueous solution of 2’-FL containing raw material provided in step a) is fed to a continuously operated crystallization apparatus, which contains an aqueous suspension of 2’-fucosyllactose crystals.

In other words, the aqueous solution of 2’-FL is continuously fed to a continuously operated crystallization apparatus and the crystallized 2’-FL is continuously discharged from the crystalli zation apparatus.

In the continuously operated crystallization apparatus, conditions of controlled supersaturation are maintained throughout the crystallization. Preferably, conditions of controlled supersatura- tion are maintained by continuously removing defined amounts of water, preferably by evapora- tion, or by cooling or by combinations of these measures.

Frequently, the continuously operated crystallization apparatus is operated in such a manner that the conditions of controlled supersaturation are quasi-statical or almost quasi-statical. In particular, temperature variations are less than 5 K and/or pressure variations are less than 60 mbar.

Generally, the continuously operated crystallization apparatus contains an aqueous suspension of 2’-FL crystals. Preferably, the solids content of the aqueous suspension contained in the con- tinuously operated crystallization apparatus, i.e. the amount of crystalline 2’-FL, is in the range from 5 to 60% by weight, in particular from 10 to 45% by weight, especially from 20 to 40% by weight, based on the total weight of the suspension contained in the continuously operated crystallization apparatus or in the active volume of the continuously operated crystallization ap- paratus. The active volume is understood as those parts of the crystallization apparatus, where the crystallization occurs, e.g. those parts which contain the free flowing aqueous suspension of 2’-FL crystals.

Frequently, step b) of the continuously operated crystallization apparatus comprises the follow- ing sub-steps:

b1) continuously feeding the aqueous solution of 2’-FL raw material to a continuously oper- ated crystallization apparatus containing an aqueous suspension of crystalline 2’-FL, which preferably contains crystalline 2’-FL in an amount from 5 to 60% by weight, in par ticular from 10 to 45%, especially 20 to 40% by weight, based on the weight of the sus- pension;

b2) continuously removing water from the aqueous suspension of 2'-FL contained in the crystallization apparatus, preferably by evaporation, in particular by evaporation under reduced pressure;

b3) continuously removing the aqueous suspension of 2'-FL from the crystallization appa- ratus.

It has been found beneficial if the stream of the aqueous suspension of 2’-FL removed from the crystallizer in step b3) is split into two streams: A first stream is subjected to an isolation of crys- talline 2’-FL, while the remainder is partly fed back to the crystallization apparatus together with fresh aqueous solution of 2’-FL raw material, provided in step b1). For this, a portion of the aqueous suspension of 2’-FL removed in step b3) is mixed with the aqueous solution of 2’-FL raw material of step b1 ) before it is fed to the crystallization apparatus. The thus obtained mix- ture is then fed back it into the crystallization apparatus. The volume ratio of the total stream removed from the crystallizer in step b3) to the first stream is subjected to an isolation of crystal- line 2’-FL is at least 4 : 1 , in particular at least 7 : 1 , more particularly at least 10 : 1 , e.g. from 4 : 1 to 200 : 1 , or from 7 : 1 to 80 : 1 or from 10 : 1 to 60 : 1.

In order to remove water by evaporation the energy necessary for evaporation must be intro- duced into the crystallizer. This may be achieved by conventional heating elements. Preferably the evaporation heat is introduced into the crystallizer by feeding a heated stream of the aque- ous solution of the 2'-FL raw material to the reactor. The heated stream of the aqueous solution of 2’-FL raw material which is fed into the reactor may be heated by any conventional heat ex- changer. The heat exchanger may be operated with conventional heating media such as heat- ing oils or heating steam, including steam from a steam network or steam provided in the meth- od for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material by vapor recompression of water evaporated during crystallization or concentration of the aqueous solu- tion of 2'-FL raw material. Preferably, the heated solution of 2’-FL raw material, which is fed into the crystallizer, is heated by using a forced circulation decompression evaporator, which is pref- erably heated by steam from vapor recompression of the water evaporated during crystallization or concentration of the aqueous solution of the 2'-FL raw material. Using a forced circulation decompression evaporator minimizes fouling on the heat exchanger surfaces. The continuously operated crystallization apparatus is preferably a forced circulation crystallizer.

The crystallization of step b) is typically carried out such that at least 30 %, in particular at least 40 %, e.g. from 30 to 95 %, in particular from 40 to 90 % of the 2’-fucosyllactose initially con- tained in the aqueous solution which is subjected to the crystallization in step b) has been crys- tallized. A skilled person will immediately appreciate that a low percentage of crystallized 2’- fucosyllactose will result in a higher purity while a high percentage crystallized 2’-fucosyllactose will result in a lower purity of the obtained crystalline 2’-fucosyllactose.

In step b) a suspension of crystalline 2’-fucosyl lactose in the aqueous mother liquor is obtained. In step c) the crystallized 2’-FL is separated from the aqueous mother liquor. For this, the sus- pension of crystallized 2’-FL in the aqueous mother liquor is subjected to solid/liquid separation. Suitable measures for the separation of solids from liquids include centrifugation, filtration, or washing towers. Means for centrifugation may include, but are not limited to, pusher centrifuges, worm screen centrifuges, peeler centrifuges and decanters. Means for filtration may include, but are not limited to, rotary pressure filters, belt filters, suction filters, chamber filters and chamber filter presses. Suitable washing towers may include, but are not limited to, gravity wash col- umns, mechanical wash columns, hydraulic wash columns and piston type wash columns. Pref- erably, solid/liquid separation is performed by centrifugation, in particular by utilizing a pusher centrifuge or a worm screen centrifuge, because thereby low residual moisture in the obtained solid can be achieved, which is frequently less than 10% by weight, e.g. from 1 to 8% by weight.

The solid/liquid separation may be performed stepwise or is performed continuously.

The obtained solid may be washed in order to remove adherent mother liquor, e.g. by cold sol- vent such as water or a saturated aqueous solution of pure 2’-FL. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mixture of water and a non-solvent for 2’- FL. Typical non-solvents are Ci-C4-alkanols, such as methanol, ethanol, n-propanol or n- butanol, and acetic acid. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mother liquor of a subsequent crystallization step, if the crystallization is per- formed in more than one crystallization stages. A suitable solvent, which can be utilized for washing of solid 2’-FL, may also be a mixture of water and a non-solvent for 2’-FL, i.e. a mixture of non-solvent and mother liquor of a subsequent crystallization step, if the crystallization is per- formed in more than one crystallization stages. Washing may be performed e.g. by spraying the solid crystalline 2'-FL with the cold solvent followed by a further liquid/solid separation or by suspending solid crystalline 2'-FL in the cold solvent followed by a further liquid/solid separation. The washing may be performed in a single step or by multiple washing steps, e.g. by 2, 3 or more steps. If the washing is performed by multiple washing steps, the washing steps may be operated concurrently or preferably countercurrently.

In order to drive crystallization to completion and to increase the yield of crystalline 2’- fucosyllactose, it is possible to add a water miscible organic solvent to the suspension of 2’- fucosyllactose in the mother liquor prior to step b), when the crystallization is almost complete.

In this context,“almost complete” is preferably understood that at least 80 %, in particular at least 90 % of the 2’-fucosyllactose has been crystallized, calculated on the basis of the amount of 2’-fucosyllactose, which can theoretically crystallize from the solution in step b) under the conditions of the crystallization chosen in step b). Typically, the organic solvent will only be added, if at least 30 %, in particular at least 40 %, e.g. from 30 to 95 %, in particular from 40 to 90 % of the 2’-fucosyllactose initially contained in the aqueous solution which subjected is sub- jected to the crystallization in step b) has been crystallized. Suitable water-miscible organic sol- vents will be completely miscible with deionized water at 20°C and 1 bar. Examples of suitable organic solvents include ethanol, acetic acid and propionic acid and mixtures thereof. The amount of organic solvent is frequently chosen such that the weight ratio of organic solvent to water is at least 1 :1 , e.g. in the range from 1 :1 to 10:1. Surprisingly, the addition of organic sol- vents results in a higher purity of the obtained 2’-fucosyllactose.

The crystallization of 2'-FL will frequently comprise a single crystallization step, as a single crys- tallization will generally ensure a purity of 2’-FL, which is sufficient for most purposes. However, the crystallization of 2'-FL may comprise two or more crystallization steps, 2 or 3 subsequent crystallization steps or stages. The further crystallization stages may involve a re-crystallization of the crystalline material obtained in the first crystallization stage. In this case, the further crys- tallization stages may be performed in accordance with the method described above involving crystallization under conditions of controlled supersaturation and are useful to further increase the purity of the desired 2’FL. It is also possible to subject the mother liquor obtained in the first crystallization stage to a second crystallization stage, in order to increase the yield of 2'- fucosyllactose. In this case, it is possible to mix the mother liquor with a portion of the aqueous solution of the 2'-fucosyllactose raw material and subject the mixture to the crystallization.

In order to increase the yield of crystalline 2’-fucosyllactose, a portion or the complete amount of the mother liquor obtained in step c) may be subjected to a crystallization of 2’-fucosyl lactose by inducing conditions of a controlled supersaturation in the mother liquor. For this, the mother liq uor may be subjected to a further crystallization, preferably according to the method as de- scribed herein. However, it is also possible to mix at least a portion of the mother liquor with the solution of the 2’-fucosyllactose raw material prior to carrying out step b) and then subject the mixture to a further crystallization of 2’-fucosyllactose according to the method as described herein.

According to a first preferred group of aspects, the multi-stage crystallization method comprises a first crystallization step and a second crystallization step, and optionally one or more, e.g. 1 or 2 further crystallization steps, where at least in the second crystallization step and preferably also in the first crystallization step the crystallization of 2’-fucosyllactose is effected by inducing conditions of a controlled supersaturation in the solution by the method as described herein. In this preferred group of aspects, the aqueous solution of the 2’-fucosyllactose raw material pro- vided in step a) is subjected to the crystallization of the second crystallization step. From this second crystallization step, an aqueous suspension of the crystalline 2’-fucosyllactose in the mother liquor is obtained which is then subjected to a solid-liquid separation according to step c) whereby crystalline 2’-fucosyllactose and a mother liquor is obtained. This mother liquor is then fed into the first crystallization step. The first crystallization step may be carried out as described herein for step b) or according to a crystallization according to the prior art. Preferably, the first crystallization step is carried out according to step b) as described herein. The first crystalliza- tion step results in an additional amount of crystalline 2’-fucosyllactose. Frequently, the purity of the crystalline 2’-fucosyllactose obtained in the first crystallization step is somewhat lower than the purity of the crystalline 2’-fucosyl lactose obtained in the second crystallization step. The crystalline 2’-fucosyllactose obtained in the first crystallization step may be used as such. How- ever, it may also be dissolved in the aqueous solution of the 2’-fucosyllactose raw material pro- vided in step a), and the thus obtained solution is subjected to the crystallization of the second crystallization step.

According to a second group of aspects of a multi-stage crystallization method, the aqueous solution of the 2'-FL raw material provided in step a) is fed to a crystallization stage (1 ), which is operated batch-wise or continuously as described above. The crystalline 2'-FL obtained in this stage (1 ) is then dissolved in water and the obtained solution is subjected to a subsequent crys- tallization step (2), where a purified crystalline 2'-FL and a further mother liquor is obtained. The mother liquor of the subsequent crystallization step (2) may be mixed with water and the mixture is then used for dissolving the crystalline 2'-FL obtained in crystallization step (1 ). The crystal- line 2'-FL obtained in stage (2) may be subjected to one or more, e.g. to 1 or 2 further crystalli zation stages (3) and (4), respectively. For example, the mother liquor of the subsequent crys- tallization step (n+1) is mixed with water and this mixture is used for dissolving the crystalline 2'- FL obtained in crystallization step (n), where n indicates the respective crystallization step. The mother liquor of the first crystallization stage may be discarded.

According to a combination of the first and the second group of aspects the mother liquor of the first crystallization stage is subjected to a further crystallization stage, also termed stripping stage, to obtain a residual mother liquor, which is discarded, and crystalline 2'-FL of lower puri ty. The crystalline 2'-FL of lower purity obtained in said crystallization stage may be dissolved, e.g. in the aqueous solution of 2'-FL provided in step a) to obtain a more concentrated solution, which is fed into the crystallization step (1). The crystalline 2'-FL obtained in said crystallization from the mother liquor of step (1) may also be dissolved in a mixture of water and the mother liquor obtained in crystallization step (1 ) and combined with the aqueous solution of 2'-FL pro- vided in step a) to obtain a more concentrated solution, which is fed into the crystallization step (1 )·

According to the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material, at least crystallization stage (1) of the second group of aspects and of the combination of the second and the first group of aspects is performed in accordance with the method de- scribed above, which involves crystallization under conditions of controlled supersaturation. If the crystallization stage is followed by the crystallization stage (2), also crystallization stage (2) is preferably performed in accordance with the method described above, which involves crystal- lization under conditions of controlled supersaturation.

The method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyl lactose raw material is described in detail hereinafter with reference to figures 5.1 to 5.9. The figures shown serve for illustration and are not intended to restrict the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material.

Description of the figures 5.1 to 5.9:

Figure 5.1 shows a basic flow chart of the method for obtaining crystalline 2’- fucosyllactose from a 2’-fucosyllactose raw material

Figure 5.2 shows one aspect of a forced circulation crystallizer.

Figure 5.3 shows another aspect of a forced circulation crystallizer, in this case a draft baffle crystallizer.

Figure 5.4 shows an aspect of induced forced circulation crystallizer.

Figure 5.5 shows a block diagram of an aspect of a multi-stage method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material.

Figure 5.6 shows a block diagram of a second group of aspects of a multi-stage method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material. Figure 5.7 shows schematically one crystallization stage of the method for obtaining crys- talline 2’-fucosyllactose from a 2’-fucosyllactose raw material.

Figure 5.8 shows schematically a two stage crystallization process according to the first group of aspect of the method for obtaining crystalline 2’-fucosyllactose from a

2’-fucosyllactose raw material.

Figure 5.9 shows schematically a two stage crystallization process according to the sec- ond group of aspect of the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material.

In the figures 5.5 to 5.9, the following reference symbols are used:

C crystalline phase / crystals

CR Crystallization

D Discharge

DU Dilution unit

F Feed

L Liquor

ML mother liquor MLR recycled mother liquor

P Product

R recycled suspension

RL residual liquor

S fresh solution

SLS solid/liquid separation

V Vapor

W condensed vapor (liquid water)

WL wash liquid i index for the stage

1 Crystallizer

2 heat exchanger

3 Separator

4 circulation pump

5 concentrate pump

6 compressor for vapor

10 Inlet

1 1 slurry withdrawal

12 suspension outlet

13 liquid withdrawal / overflow

14 draft tube

15 Demister

16 vapor outlet

17 settling zone

18 Agitator

19 Inducer

20 vapor separation zone

21 active volume

Figure 5.1. As illustrated in figure 5.1 , a fresh stream S containing an aqueous solution of the 2'- FL raw material is combined with a recycle stream R and heated in a heat exchanger 2 to a temperature of at least 40°C, for example in the range of from 40°C to 95°C, to give an aqueous solution of the 2'-FL raw material as feed stream F. The heat exchanger 2 can be arranged ei- ther horizontally or vertically depending on the specific requirements. The feed F is then fed to a continuously operated crystallizer 1. The crystallizer 1 contains as active volume an aqueous supersaturated suspension of 2'-FL with a content of solid 2’-FL of 5% to 50% by weight, for example from 20% to 40% by weight, based on the weight of the suspension. Feeding the un- der-satu rated aqueous solution of 2'-FL raw material F into the active volume and removing water at the same time, the concentration of 2'-FL in the over-saturated suspension, i.e. in the active volume of the crystallizer 1 is levelled off. The controlled supersaturation of 2'-FL in the aqueous suspension is effected at a temperature of at least 25°C, for example in the range of from 30°C to 95°C, depending from the desired polymorph of 2’-FL, and at reduced pressure, for example in the range of from 20 mbar to 800 mbar. Water is removed from the aqueous suspension of 2'-FL by evaporation, the water vapor V being withdrawn at the head from the crystallizer 1. The vapor V can be further conveyed via a compressor 6 to heat the heat ex- changer 2, conducted for example in countercurrent to the feed F to be heated, and leaving the heat exchanger 2 as condensate W. A discharge D of the slurry containing crystalline 2'-FL is removed at the lower end from the crystallizer 1. From the discharge D, a partial stream is taken as recycle stream R and conveyed via a recycling pump 4 to be mixed with the fresh stream S before, on or after entry into the heat exchanger 2. The discharge D will be portioned in such a way that the mass ratio of the recycle stream R to the fresh stream S is preferably greater than 5, in particular greater than 10, greater than 20, for example in the range of from 40 : 1 to 60 : 1. The other part of the discharge D is routed by means of a concentrate pump 5 to a separator 3. In the separator 3, the slurry D is separated to obtain mother liquor ML and crystalline 2'-FL as product P. If desired, the mother liquor ML can be recycled to the method for obtaining crystal- line 2’-fucosyllactose from a 2’-fucosyllactose raw material or a preceding stage. Alternatively, a discharge D of the slurry containing crystalline 2'-FL is removed on the side of the lower end from the crystallizer 1. The discharge D is routed by means of a concentrate pump 5 to a sepa- rator 3. In the separator 3, the slurry D is separated to obtain mother liquor ML and crystalline 2'-FL as product P. If desired, the mother liquor ML can be recycled to the method for obtaining crystalline 2’-fucosyllactose from a 2’-fucosyllactose raw material or a preceding stage. A sec- ond discharge is removed as recycle stream R in the center part of the lower end from the crys- tallizer 1. The recycle stream R is conveyed via a recycling pump 4 to be mixed with the fresh stream S before, on or after entry into the heat exchanger 2. The mass ratio of the recycle stream R to the fresh stream S is greater than 5, in particular greater than 10, greater than 20, for example in the range of from 40 : 1 to 60 : 1. This alternative withdrawal of two different slur ries can prove in particular advantageous if the slurry D taken at the side of the crystallizer is thicker or contains crystals of a different size distribution than the slurry R taken at the bottom of the crystallizer 1. The crystallization may be preferably effected in a continuously operated crys- tallizer, for example a forced circulation crystallizer, a draft tube crystallizer or a draft tube baf- fled crystallizer, or in particular in an induced forced circulation crystallizer.

Figure 5.2 shows a draft tube crystallizer. Superheated aqueous solution of the 2'-FL raw mate- rial F is fed to the crystallizer 1 via an inlet 10, flows upward through a draft tube 14 and returns downward along the outer side of the draft tube 14. Water evaporated from the suspension in the active volume 21 rises as vapor V to the head of the crystallizer 1. The vapor V passes a vapor separation zone 20 and a demister 15 to remove liquid droplets and leaves the crystalliz er 1 via a vapor outlet 16. The vapor V is further conveyed via a compressor 6 to heat the heat exchanger 2, conducted for example in countercurrent to the feed F to be heated, and leaving the heat exchanger 2 as condensate W. Around the active volume 21 , a settling zone 17 may be arranged. Via a suspension outlet 12 in the lower region of the active volume 21 , suspension R is removed and combined with the fresh solution S. The combined stream of R and S is recy- cled via a circulation pump 4 through a heat exchanger 2 as feed F into the crystallizer. The circulation pump 4 provides for the necessary agitation of the suspension mixed with the incom- ing solution F and effects the circulation of the suspension within the active volume 21. Via a slurry withdrawal 1 1 situated at the bottom of the crystallizer 1 below the active volume 21 , slur ry D is removed from the crystallizer 1. The withdrawn slurry D contains the desired crystalline 2'-FL.

Figure 5.3 shows a draft tube baffled crystallizer with forced circulation. Superheated aqueous solution of 2'-FL raw material F is fed to the crystallizer 1 via an inlet 10, flows upward through a draft tube 14 and returns downward along the outer side of the draft tube 14. A bottom entry agitator 18 provides for the necessary agitation of the suspension mixed with the incoming solu- tion F at moderate energy consumption and effects the circulation of the suspension within the active volume 21. Water evaporated from the suspension in the active volume 21 rises as vapor V to the head of the crystallizer 1. The vapor V passes a vapor separation zone 20 and a de- mister 15 to remove liquid droplets and leaves the crystallizer 1 via a vapor outlet 16. Peripheral to the active volume 21 , a settling zone 17 is arranged by means of baffles. In the settling zone 17, excess mother liquor L and/or fines can be withdrawn for further processing at an overflow 13 in the upper region of the settling zone 17. This basically clear liquor L can be recycled to the process to regulate the temperature and/or the concentration of the solution of 2'-FL at any stage. Via a suspension outlet 12 in the lower region of the settling zone 12, suspension R is removed and recycled to be mixed with the fresh feed stream S. Via a slurry withdrawal 11 situ- ated below the settling zone 12, slurry D is removed from the crystallizer 1. The withdrawn slurry D contains the desired crystalline 2'-FL as product P.

Figure 5.4. The induced forced circulation crystallizer shown in figure 5.4 operates similarly to the forced circulation crystallizers shown in figures 5.2 and 5.3 as explained above. Different to the aspect shown in figure 5.3, the induced forced circulation crystallizer works without any in- ternal agitation device. Superheated aqueous solution of 2'-FL raw material F is fed to the crys- tallizer 1 via an inlet 10, flows upward through a draft tube 14 and returns downward along the outer side of the draft tube 14. Water evaporated from the suspension in the active volume 21 rises as vapor V to the head of the crystallizer 1. The vapor V passes a vapor separation zone 20 and a demister 15 to remove liquid droplets and leaves the crystallizer 1 via a vapor outlet 16. Peripherical to the active volume 21 , a settling zone 17 is arranged. Liquor L is withdrawn at a liquid withdrawal 13 in the upper region of the settling zone 17. This basically clear liquor L is recycled via the circulation pump 4. Via a suspension outlet 12 below the settling zone 12, sus- pension R is removed and combined with the clear liquor L in an external circuit. Fresh solution S is fed to the recycled stream L before, simultaneously or after combination with stream R. The combined recycled stream is heated in a heat exchanger (not shown in the figure) and fed to the crystallizer 1 as feed F. Analogously to the aspect shown in figure 5.2, the vapor V may be used to heat the heat exchanger 2. The throughput of the circulation pump 4 provides for the syphon ing of the recycled suspension R and the necessary agitation of the suspension within the active volume 21. No further agitation devices are required, so that the crystals in the suspension are treated with the least possible strain. Via a slurry withdrawal 11 situated at the bottom of the crystallizer 1 below the active volume 21 and below the settling zone 12, slurry D is removed from the crystallizer 1. The withdrawn slurry D contains the desired crystalline 2'-FL as product P.

Figure 5.5. In the multi-stage process according to figure 5.5, the crystallization is performed in n stages. It should be noted that stages 3 to n are optional stages. A feed F is introduced into a first crystallization stage (i = 1). Solvent is removed from the first crystallization e.g. by way of evaporation. The suspension is separated into residual liquor RL and a first crystalline phase Ci. The first crystalline phase Ci is passed into a second crystallization stage (i = 2). Mother liquor from the second crystallization stage (i = 2) is recycled into the first crystallization stage (i = 1), e.g. by mixing it with water and using the mixture for dissolving the crystalline phase Ci obtained in the first crystallization stage. In each crystallization stage (i = 2 to n), water is re- moved, e.g. by withdrawing it in the form of solvent vapor V and the suspension is separated into mother liquor ML and a crystalline phase C. The crystalline phase from each crystallization stage (i) is passed into the following crystallization stage (i+1). Mother liquor from each crystalli zation stage (i) is recycled into the previous crystallization stage (i-1 ), for example by mixing it with water and utilizing the mixture for dissolving the crystalline 2'-FL from the previous crystalli zation stage. A crystalline phase containing the desired 2'-FL crystals is withdrawn from the last stage n. The number of stages n depends on the desired quality of the crystals in respect of form, purity, flow characteristics and storage properties.

Figure 5.6. In the multi-stage process according to figure 5.6, the crystallization is performed in n stages, the first stage (i = 1) being a stripping section. It should be noted that stages 3 to n are optional stages. The flow is similar to the flow described in figure 5.5, but feed F is introduced between the stripping stage (i = 1 ) and the second crystallization stage (i = 2). In general, the process according to figure 5.6 gives higher yields of the desired product.

Figure 5.7. A crystallization stage (i) according to figure 5.7 comprises an apparatus each for crystallization CR, and for solid/liquid separation SLS,. Apparatuses employed for the crystalliza- tion CRi are in general crystallizers suitable for crystalline suspensions such as stirred tank re- actors, e.g. Swenson type crystallizers, forced circulation crystallizers, e.g. Oslo type reactors, draft tube reactors, draft tube baffled crystallizer (see figure 5.3), or induced forced circulation crystallizer (see figure 5.4). Apparatuses employed for the solid/liquid separation SLS, are in general centrifuges, decanters, filters, filter presses, or washing towers. The feed F, for each stage (i) comprises suspension containing the crystalline phase CM from the previous stage (i-1) and/or fresh feed F, respectively, as well as recycled mother liquor MLR,. Distillate is withdrawn from the crystallization CR, in the form of solvent vapor V,. Subsequently, the suspension is separated in the solid/liquid separation SLS, into mother liquor ML and a crystalline phase C,. The crystalline phase C, from each crystallization stage (i) can be passed as feed F _M into the following crystallization stage (i+1) or be withdrawn as product, respectively. One portion of mother liquor ML from each crystallization stage (i) is recycled into the same stage as MLR,.

The rest of mother liquor ML from each crystallization stage (i) can be recycled into the previous crystallization stage (i-1 ) or be withdrawn, respectively. To enhance the purity of the product 2'- FL, washing liquid WL can additionally be employed in the solid/liquid separation SLS,. As washing liquid WL cold water or cold mother liquor of a subsequent crystallization stage (i+1) is preferably used.

Figure 5.8. In figure 5.8, a two stage process similar to figure 5.6 is depicted. The feed F is in- trod uced between the stripping stage (i = 1) and the second crystallization stage (i = 2) into a dilution unit DU, where the crystalline 2’-fucosyllactose C1 obtained in the first crystallization stage is dissolved in the feed, i.e. in the aqueous solution of the 2’-fucosyllactose raw material. Water is removed from the second crystallization stage e.g. as vapor V by way of evaporation. Thereby a suspension of 2’-fucosyl lactose in the mother liquor is obtained, which is subjected to a solid-liquid separation SLS2 to obtain a mother liquor ML and the purified crystalline 2’- fucosyllactose C2. The mother liquor from the second crystallization stage (i = 2) is recycled into the first crystallization stage (i = 1 ). Water is removed from the first crystallization stage e.g. as vapor V by way of evaporation. Thereby a suspension of 2’-fucosyllactose in a mother liquor is obtained, which is subjected to a solid-liquid separation SLS1 to obtain a residual liquor RL, which is discarded, and the crystalline 2’-fucosyllactose C1.

Figure 5.9. In figure 5.9, a two stage process similar to figure 5.5 is depicted. The feed F, i.e. the aqueous solution of the 2’-fucosyllactose raw material, is introduced into the first crystalliza- tion stage (i = 1 ). Water is removed from the first crystallization stage e.g. as vapor V by way of evaporation. Thereby a suspension of 2’-fucosyllactose in the mother liquor is obtained, which is subjected to a solid-liquid separation SLS1 to obtain a residual liquor RL, which is discarded, and a purified crystalline 2’-fucosyllactose C1. The crystalline 2’-fucosyl lactose C1 is dissolved in solvent S (water or in further feed) in a dilution unit DU. The thus obtained solution is passed into a second crystallization stage (i = 2). Water is removed from the second crystallization stage e.g. as vapor V by way of evaporation. Thereby a suspension of 2’-fucosyllactose in the mother liquor is obtained, which is subjected to a solid-liquid separation SLS2 to obtain a moth- er liquor ML and the purified crystalline 2’-fucosyllactose C2. Mother liquor ML from the second crystallization stage (i = 2) is recycled into the first crystallization stage (i = 1), e.g. by mixing it with the feed F.

Abbreviations:

2’-FL: 2’-0-fucosyllactose DiFL: difucosyllactose

b.w.: by weight

rpm: rotations per minute

RT: Room temperature, i.e. about 22°C

Analytics:

HPLC:

Column: Spherisorb NH2 column (amine modified silica: particle size 3pm, pore size 8qA) length 250 mm, internal diameter 4.5 mm (Waters Corporation)

Eluent: acetonitrile/water 82.5/17.5 v/v

Detection: RID

Parameters: flow rate 1.3 ml/min, T = 35°C, pressure 1 12 bar, 5 pi injection volume Determination of water: The concentration of water was determined by Karl-Fischer titra tion.

Dry matter content was determined by drying 2g of the sample at 130°C for 2 hours Filter cake resistance was calculated based on the measured volume flow of the filtrate in the pressure nutsche, the applied pressure and the filter area.

Determination of crystalline form: Powder X-Ray Diffraction (PXRD)

X-ray diffraction patterns were recorded with a Panalytical X ^' Pert Pro diffractometer (manufacturer: Panalytical) in reflection geometry (Bragg-Brantano) in the range from 2Q = 3° - 40° with increments of e.g. 0.017° and measurement time of 20 s/step using Cu-Ka radiation (1.54178 A) at 25°C. The tube voltage was 45 kV and current 40 mA. The sam- ple was placed in a silicon single crystal sample holder of 0.2 mm depth and flattened.

Crystallization Examples:

In examples I to III an aqueous solution of a 2’-FL raw material was used, which was obtained by fermentation and subsequent downstream processing including passing the fermentation broth through a bed of an ion exchange resin and concentration of the thus treated broth to a solids content of 61.1 % by weight was used. The aqueous solution contained 52.5% by weight of 2’-FL and 8.6% by weight of mono- and oligosaccharides including lactose, DiFL and fucosyl- lactulose.

Example I:

In a reaction flask equipped with a distillation bridge and a stirrer 100 g of the aqueous solution of the 2’-FL raw material was heated by means of a water bath to 50°C (bath temperature). At a pressure of 30 mbar 19.42 g of water were distilled off resulting in a syrup containing 65% by weight of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.74 : 1. The vessel was expanded to ambient pressure and the resulting viscous solution was allowed to cool to 45°C (bath temperature) and seeded with 0.05 g of crystalline Form II of 2’-FL ob- tained from a previous run. The mixture was stirred at 45°C (bath temperature) for further 4 h, allowed to cool to RT and stirred for further 16 h. The thus obtained thick suspension was warmed to 35°C (bath temperature) and stirred for 2 h at 35°C at ambient pressure. The warm suspension was filtered through a heated suction filter (35°C) and the filter cake was washed 4 times with each 10 ml of ethanol/water (80/20 w/w) and thereafter dried at 40°C and 0.8 mbar for 12 h. Thereby, 38.9 g of crystalline material (yield 70.5%) having the following composition was obtained: Composition (HPLC): 95.1 % 2’-FL, 0.2% lactose, 0.3% fucosyllactulose, 0.9% DiFL. The obtained crystalline material contained 3.3% by weight of water as determined by Karl-Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form A, as determined by PXRD.

Example II:

In a reaction flask equipped with a distillation bridge and a stirrer 200 g of the aqueous solution of the 2’-FL raw material was heated by means of a water bath to 55°C (bath temperature). At a pressure of 30 mbar 31.65 g of water were distilled off resulting in a syrup containing 62.4% by weight of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.3 : 1. The resulting viscous solution was expanded to ambient pressure and allowed to cool to 45°C (bath temperature) and seeded with 0,05 g of crystalline 2’-FL obtained from example I (Form A). The mixture was stirred at 45°C (bath temperature) and ambient pressure for further 4 h and then cooled to 10°. A sample was taken which showed that form A of 2’-FL had been formed. Then 136.2 ml of acetic acid was added (to obtain a ratio of acetic acid to water of about 3/1 v/v) within 30 min while keeping the temperature at 10°C and the obtained suspension was stirred for 0.5 h at 10°C at ambient pressure. The thus obtained suspension filtered through a suction filter and the filter cake was washed 3 times with each 10 ml of acetic acid/water (80/20 w/w) and thereafter dried at 40°C and 0.8 mbar for 12 h. Thereby, 53.6 g (yield 49.1 %) of crys- talline material having the following composition was obtained: Composition (HPLC): 0.5% DiFL and 96.2% 2’-FL (no detectable amounts of lactose and fucosyllactulose). The obtained crystal- line material contained 3.9% by weight of water as determined by Karl-Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form A, as determined by PXRD.

Example III:

In a reaction flask equipped with a distillation bridge and a stirrer 200 g of the aqueous solution of the 2’-FL raw material was heated by means of a water bath to 65°C (internal temperature; 80°C bath temperature). At a pressure of 250 mbar 38 g of water were distilled off resulting in a syrup containing 64.8% by weight of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.5 : 1. The resulting syrup was expanded to ambient pressure and allowed to cool to 50°C (bath temperature). The suspension was stirred at 50°C at ambient pressure (bath temperature) for further 3 h and then cooled to 20°C and stirred for further 1 h at 20°C. Then 117 ml of acetic acid was added (to obtain a ratio of acetic acid to water of about 3/1 v/v) within 30 min while keeping the temperature at 20°C and the obtained suspension was stirred for 0.5 h at 10°C. The thus obtained suspension filtered through a suction filter and the filter cake was washed 3 times with each 15 ml of acetic acid/water (80/20 w/w) and thereafter dried at 40°C and 0.8 mbar for 12 h. Thereby, 80.3 g (yield 75.6%) of crystalline material having the following composition was obtained: Composition (HPLC): 0.2% lactose, 0.3% fucosyllactulose and 98.8% 2’-FL (no detectable amounts of DiFL). The obtained crystalline material contained 0.015% by weight of water as determined by Karl-Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form II, as determined by PXRD.

As variations to Example III above, the following are possible:

a. Instead of concentration the 2’-FL-raw material to above 60 weight % in the syrop as de- tailed in Example III, it is also possible to use less high concentrated solutions of 2’-FL raw material of only up to 50 weight % 2’-FL in solution. The results of the experiment per- formed starting from those less concentrated solutions is basically the same as in Exam- pie III.

b. As a further possibility, the amount of acetic acid as used in Example III can be increased in its amounts up to 3-fold, still leading to the basically same results as in Example III. c. As a further possibility, the solution could be seeded with any polymorphic form of 2‘-FL and even with amorphous 2’-FL at the stage immediately prior to the first addition of acetic acid (with relative amount comparable to those of example II above) also yielding the ba- sically same results.

“Basically the same results” means that the absolute amounts of the purity of 2’-FL and the con- tents of the by-products vary to a very small extent, i.e. about less than 5% deviation from the experimental results of Example III.

In example IV, an aqueous solution of a 2’-FL raw material was used, which was obtained by fermentation and subsequent downstream processing including passing the fermentation broth through a bed of an ion exchange resin and concentration of the thus treated broth to a solids content of 61.5% by weight was used. The aqueous solution contained 49.4% by weight of 2’- FL and 12.1 % by weight of mono- and oligosaccharides including 0.8% of lactose, 0.4% of fu- cosyllactulose and 2.5% of DiFL.

Example IV:

In a reaction flask equipped with a distillation bridge and a stirrer 200 g of the aqueous solution of the 2’-FL raw material was heated by means of a water bath to 45°C (bath temperature). At a pressure of 20 - 50 mbar about 30 g of water were distilled off resulting in a syrup containing about 58% by weight of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.1 : 1. The resulting viscous syrup was expanded to ambient pressure and seeded 45°C (bath temperature) with 0.05 g of crystalline 2’-FL obtained from example III (Form II). The mix- tu re was stirred at ambient pressure and 45 °C (bath temperature) for further 16 h. The thus obtained thick suspension was discharged from the reactor and filtered through a heated suc- tion filter (40°C) and the filter cake was dried at 40°C and 10 mbar for 16 h under a flow of inert gas. Thereby, 78.1 g of crystalline material (yield 69.3%) having the following composition was obtained: Composition (HPLC): 0.72% lactose, 0.57% fucosyllactulose, 2.61 % DiFL and 87.64% 2’-FL. The obtained crystalline material contained 3.0% by weight of water as deter- mined by Karl-Fischer titration. In the obtained crystalline material 2’-FL was present essentially as form A, as determined by PXRD.

In the following examples V to VIII and comparative examples C1 and C2 an aqueous solution of a 2’-FL raw material was used, which was obtained by fermentation and subsequent down- stream processing including decolorization, microfiltration, ultrafiltration, demineralization and reverse osmosis. The aqueous solution had a dry matter content of 25 % by weight and con- tained 21.0 % by weight of 2’-FL and 4% by weight of mono- and oligosaccharides including lactose and DiFL.

Example V:

In a rotary evaporator the aqueous solution of a 2’-FL raw material was evaporated at 60°C un- der reduced pressure to a dry matter content of about 73 % by weight and a concentration of 2’- FL of about 59 % by weight. 1517 g of the thus obtained solution were filled into a baffled tank and stirred at 60°C (internal temperature). Then, 12 g of amorphous 2’-FL were added to this solution and formation of solids was observed. The thus formed suspension was stirred for 20 h at 60°C (internal temperature). Then, the thus formed suspension was cooled within 1.5 h to 25 °C with stirring. The thus obtained suspension was then filtered without washing. Thereby, 467 g of a wet crystalline material having the following composition was obtained: Composition of the filter cake: 83 % b.w. 2’-FL, 1.2% b.w. lactose, 0.9% b.w. fucosyllactulose, 2.1 % b.w. DiFL and 9 % b.w. water. In filter cake 2’-FL was present essentially as form II, as determined by PXRD. The calculated yield was 42 % based on the fucosyllactose contained in the concentrat- ed solution. The filtrate had the following composition: 49 % b.w. 2’-FL, 1.4 % b.w. fucosyllactu- lose, 2% b.w. lactose, 3.7% b.w. DiFL and 36 % b.w. water. The filter cake resistance was 5x10 ¹² Pas/m ² .

The same variations a. to c. as mentioned in Example III are here applicable as well, leading to the basically same results as in Example V.

Example VI:

In a rotary evaporator the aqueous solution of a 2’-FL raw material was evaporated at 40°C un- der reduced pressure to a dry matter content of about 62 % by weight and a concentration of 2’- FL of about 50 % by weight. 1532 g of the thus obtained solution were filled into a baffled tank and stirred at 40°C (internal temperature). Then, 5 g of crystalline 2’-FL (form II) were added to this solution and formation of solids was observed. The thus formed suspension was stirred for 19 h at 40°C (internal temperatu re) .Then , the thus formed suspension was evaporated at 40°C under reduced pressure to a concentration of 2’-FL of 61 % by weight and thereafter cooled within 1.0 h to 25 °C with stirring. The suspension was stirred for further 22 h at 25°C. The thus obtained suspension was then filtered without washing. Thereby, 772 g of wet crystalline mate- rial having the following composition was obtained: Composition of the filter cake: 77% b.w. 2’- FL, 1.1 % b.w. lactose, 0.8% b.w. fucosyllactulose, 1.9% b.w. DiFL and 15 % b.w. water. The calculated yield was 77 % based on the 2’-FL contained in the concentrated solution. In filter cake 2’-FL was present essentially as form B, as determined by PXRD. The filtrate had the fol- I owing composition: 36% b.w. 2’-FL, 2 % b.w. fucosyllactulose, 3.1 % b.w. lactose, 5% b.w.

DiFL and 40 % b.w. water. The filter cake resistance was 4x10 ¹¹ Pas/m ² .

Example VII:

In a rotary evaporator the aqueous solution of a 2’-FL raw material was evaporated at 40°C un- der reduced pressure to a dry matter content of about 65 % by weight and a concentration of 2’- FL of about 52 % by weight. 1572 g of the thus obtained solution were filled into a baffled tank and stirred at 40°C (internal temperature). Then, 26 g of crystalline 2’-FL (form A) were added to this solution and formation of solids was observed. The thus formed suspension was stirred for 1 h at 40°C (internal temperature). Then, the thus formed suspension was evaporated at 40°C under reduced pressure to a concentration of 2’-FL of 55 % by weight followed by stirring for 12 h at 40°C and subsequent cooling within 1.0 h to 25 °C with stirring. The suspension was stirred for further 7 h at 25°C. The thus obtained suspension was then filtered without washing. There- by, a wet crystalline material was obtained, which contained 2’-FL as its form B, as determined by PXRD. After drying the filter cake for 2 days at 60°C and 100 mbar crystalline material hav- ing the following composition was obtained: 90% b.w. 2’-FL, 0.5% b.w. lactose, 0.3% b.w. fuco- syllactulose, 1.1 % b.w. DiFL and 5.9 % b.w. water. The calculated yield was 41 % based on the 2’-FL contained in the concentrated solution. In the dry crystalline material 2’-FL was present essentially as form A, as determined by PXRD. The filtrate had the following composition: 45% b.w. 2’-FL, 1.3 % b.w. fucosyllactulose, 1.9% b.w. lactose, 3.7% b.w. DiFL and 39 % b.w. water. The filter cake resistance was 5x10 ¹¹ Pas/m ² .

Example VIII:

The filtrates obtained in examples V, VI and VII and water to a total of 1099 g were filled into a baffled tank and stirred at 40°C. The concentration of 2’-FL in this solution was 36 % by weight. Stirring was continued while water was evaporated from the solution at 40°C under reduced pressure until the concentration of 2’-FL was 43 % by weight (dry matter content was 67 % by weight). Then, 8 g of crystalline 2’-FL (form A) were added to this solution and formation of sol- ids was observed. The thus formed suspension was stirred for 2 h at 40°C (internal tempera- ture).Then, the thus formed suspension was evaporated at 40°C under reduced pressure to a concentration of 2’-FL of 47 % by weight followed by stirring for 1 h at 40°C and subsequent cooling within 1.0 h to 25 °C with stirring. The suspension was stirred for further 72 h at 25°C. The thus obtained suspension was then filtered without washing. Thereby, a wet crystalline ma terial was obtained, which contained 2’-FL as its form B. After drying the filter cake for 2 days at 60°C and 100 mbar crystalline material having the following composition was obtained: 88% 2’- FL, 0.9% b.w. lactose, 0.5% b.w. fucosyllactulose and 1.7% b.w. DiFL. The calculated yield was 26 % based on the 2’-FL contained in the concentrated solution. In the dry crystalline material 2’-FL was present essentially as form A, as determined by PXRD. The filtrate had the following composition: 40% b.w. 2’-FL, 2.1 % b.w. fucosyllactulose, 3.2% b.w. lactose, 5.7% b.w. DiFL and 35 % b.w. water. The filter cake resistance was 6x10 ¹¹ Pas/m ² .

Comparative Example C1 :

In a distillation apparatus the aqueous solution of a 2’-FL raw material was evaporated at 60°C under reduced pressure to a concentration of 2’-FL of about 42 % by weight. 1663 g of the thus obtained solution were filled into a baffled tank and evaporated at 60°C under reduced pressure to a dry matter content of 85 % by weight and concentration of 2’-FL of 69 %. Then spontane- ous crystallization occurred and the viscosity of the suspension was too high to drain it off the baffled tank. A PXRD of the suspension showed that the 2'-FL was present essentially as form

Comparative Example C2:

In a distillation apparatus the aqueous solution of a 2’-FL raw material was evaporated at 50°C under reduced pressure to a concentration of 2’-FL of about 50 % by weight. 1607 g of the thus obtained solution were filled into a baffled tank and evaporated at 40°C under reduced pressure to a dry matter content of 80 % by weight and concentration of 2’-FL of 65 %. Then spontane- ous crystallization occurred and the viscosity of the suspension was too high to drain it off the baffled tank. A PXRD of the suspension showed that the 2'-FL was present essentially as form B.

In the following examples IX to X an aqueous solution of a 2’-FL raw material was used, which was obtained by fermentation and subsequent downstream processing including decolorization, microfiltration, ultrafiltration, demineralization and reverse osmosis. The aqueous solution had a dry matter content of 29 % by weight and contained 24.5 % by weight of 2’-FL and 4% by weight of mono- and oligosaccharides including lactose and DiFL. The aqueous solution of a 2’- FL raw material was concentrated in a rotary evaporator under reduced pressure to a concen- tration of 2’-FL of about 52.1 % by weight. The solution is termed“pre-evaporated feed” and was used in the following examples IX and X. Example IX:

1612 g of pre-evaporated feed were filled into a baffled tank and stirred at 60°C (internal tem- perature). Water was evaporated under reduced pressure with stirring at 60°C to a concentra- tion of 62 % be weight of 2’-FL. Then, 12 g of crystalline 2’-FL (form II), suspended in a small volume of the pre-evaporated feed, were added to this solution and formation of solids was ob- served. The thus formed suspension was stirred for 19 h at 60°C (internal temperature) with stirring at 450 rpm. Then, the thus formed suspension was filtered without washing by using a heated pressure nutsche (60°C, pressure difference 0.5 bar, 230 s). Thereby, a wet crystalline material was obtained, which contained 2’-FL as its form II as evidenced by PXRD. The filter cake was dried for 1 day at 60°C and 100 mbar. The obtained crystalline material had the fol- I owing composition: 94.6% b.w. 2’-FL, 0.8% b.w. lactose, 2.1 % b.w. DiFL. The calculated yield was 45 % based on the 2’-FL contained in the concentrated solution.

The same variations a. to c. as mentioned in Example III are here applicable as well, leading to the basically same results as in Example IX.

Example X:

1628 g of pre-evaporated feed were filled into a baffled tank and stirred at 40°C (internal tem- perature). Water was evaporated under reduced pressure with stirring at 40°C to a concentra- tion of 63 % be weight of 2’-FL. Then, 13 g of crystalline 2’-FL (form A), suspended in a small volume of the pre-evaporated feed, were added to this solution and formation of solids was ob- served. The thus formed suspension was stirred for 21 h at 40°C (internal temperature) with stirring at 450 rpm. Then, the thus formed suspension was filtered without washing by using a heated pressure nutsche (40°C, pressure difference 0.5 bar, 403 s). Thereby, a wet crystalline material was obtained, which contained 2’-FL as its form B as evidenced by PXRD. The filter cake was dried for 1 day at 60°C and 100 mbar. The obtained crystalline material had the fol- I owing composition: 88% b.w. 2’-FL, 1.4% b.w. lactose, 4.3% b.w. DiFL. The calculated yield was 80 % based on the 2’-FL contained in the concentrated solution. PXRD of the dried crystal- line material showed that 2’-FL was essentially present as form A, as determined by PXRD.

Example XI:

An aqueous solution of a 2’-FL raw material was used, which was obtained by fermentation and subsequent downstream processing including passing the fermentation broth through a bed of an ion exchange resin and concentration of the thus treated broth to a 2’-FL content of 50.4 % by weight. The aqueous solution additionally contained 0.9 % by weight of lactose, 2.9 by weight of DiFL and 1.6 % by weight of fucosyllactulose. In a reaction flask equipped with a distil- lation bridge and a stirrer 150 g of the aqueous solution of the 2’-FL raw material was heated by means of a water bath to 50°C (bath temperature). At a pressure of 30-100 mbar water was distilled off resulting in a syrup containing 65% by weight of 2’-FL. The vessel was expanded to ambient pressure and the resulting viscous solution was allowed to cool to 45°C (bath tempera- ture) and seeded with 0.15 g of crystalline 2’-FL obtained from a previous run. The mixture was stirred at 45°C (bath temperature) for further 4 h, allowed to cool to RT and stirred for further 30 h at RT. To the thus obtained thick suspension 84 g of glacial acetic acid were added and the mixture was stirred for further 3 h to complete crystallization. The suspension was filtered through a suction filter and the filter cake was washed 3 times with glacial acetic acid and thereafter dried at 40°C and 1.0 mbar for 12 h. Thereby, 61 g of crystalline material having the following composition was obtained: Composition (HPLC): 92.9% 2’-FL, 0.1 % lactose, 0.1 % fucosyllactulose, 0.4% DiFL and 0.6 % acetic acid. The obtained crystalline material contained 3.6% by weight of water as determined by Karl-Fischer titration. In the obtained crystalline ma terial 2’-FL was present essentially as form A, as determined by PXRD.

Example XII

200 g of the aqueous solution of the 2’-FL raw material - which was obtained by fermentation and subsequent downstream processing including passing the fermentation broth through a bed of an ion exchange resin and concentration of the thus treated broth to a 2’-FL content of 51.3 % by weight - was heated to 65 °C. At a pressure of 250 mbar 38 g of water were distilled off resulting in a syrup containing 64.9 % by weight of 2’-FL. The weight ratio of product (2’-FL) to water in the obtained syrup was 2.5 : 1. The resulting syrup was expanded to ambient pressure and allowed to cool to 50°C (bath temperature). The suspension was stirred at 50 °C at ambient pressure (bath temperature) for further 3 hours and then cooled to 20 °C and stirred for further 1 h at 20 °C. Then 1 17 ml of acetic acid (to yield approximately acetic acid to water-ratio of 3/1 v/v) was added within 30 min while keeping the temperature at 20 °C; the obtained suspension was stirred for 0.5 h at 10 °C. The thus obtained suspension was filtered through a suction filter, and the filter cake was washed 3 times with each 15 ml of acetic acid/water (at a ratio of 80/20 w/w) and thereafter dried at 40 °C and 0.8 mbar for 12 h. Thereby, 80.3 g (yield 75.6 %) of crys- talline material having the following composition was obtained: Composition (HPLC): 0.2 % lac- tose, 0.3 % fucosyllactulose and 98.8 % 2’-FL (no detectable amounts of DiFL). The obtained crystalline material contained 0.015 % by weight of water as determined by Karl-Fischer titra tion. In the obtained crystalline material 2’-FL was present essentially as form II, as determined by PXRD. The alpha:beta-anomeric ratio was 1 ,01 :1 (i.e.“about 50:50”).

The same variations a to c as mentioned in Example III are here applicable as well, leading to the basically same results as in Example XII.