REFERENCE TO SEQUENCE LISTING SUBMITTED VIA EFS-WEB

[0001] This application includes an amino acid sequence listing in computer readable from (CRF) and conforming to the requirements of 37 C.F.R. 1.821 through 1.825. The sequence listing of this application is being submitted to the USPTO via the EFS-WEB server as authorized and set forth in MPEP § 502.05. The sequence listing of this application is filed in an ASC II text (.txt) file as identified below and is hereby incorporated by reference into the specification of this application in its entirety and for all purposes.

BACKGROUND

[0002] The present disclosure relates to liquid enzyme formulations containing one or more alpha-amylases. Alpha-amylases are useful in a variety of industrial applications such as starch processing, production of a food product, a biofuel, a cleaning product, an animal feed, or a paper pulp, and enhanced oil recovery. The present disclosure further relates to methods of making and using a liquid enzyme formulation containing one or more enzymes, such as an alpha-amylase, a protease, a cellulase, a glucoamylase having improved stability.

[0003] Currently, some alpha-amylase formulations maintain the enzyme at a high pH (pH 10.7) environment. Alpha-amylases in high pH formulation may have a lowered stability at this high pH range, which can result in a shortened product shelf life. In addition, there are few stable, compatible, and regulatory approved buffering agents for a high pH formulation. Without a buffer, pH of the alpha-amylase formulation can be unstable, and may drift lower over time. Further, there is potential of microbial growth due to the lack of a functioning preservative because food grade preservatives do not work quite well in this pH range. While the high pH initially has some anti-microbial effect, the pH eventually drifts down. The formulation may also be incompatible with most of the common formulations of other enzyme products, which are usually in neutral or slightly acidic pH range. Sometimes it is advantageous to mix two alpha-amylases of different properties during starch hydrolysis. For example, mixing high temperature active alpha-amylase with a low temperature active alpha-amylase may increase the break down the starch into oligo saccharides and lower the viscosity of the feed stock. Due to the extreme pH difference of different enzyme formulations, it is difficult to blend an alpha-amylase with a high pH formulation with different enzyme(s) having a low pH formulation.

SUMMARY

[0004] Some embodiments disclosed herein provide liquid enzyme formulations comprising: (a) an alpha-amylase; (b) a buffering agent; (c) a stabilizer; and (d) a preservative, wherein the pH of the enzyme formulation is about pH 6.0-8.0.

[0005] In some embodiments, the pH of the liquid enzyme formulation is about pH 6.3-6.7. In some embodiments, the stabilizer comprises sucrose, sorbitol, mannitol, glycerol, trehalose, sodium chloride, sodium sulfate, or any combination thereof. In some embodiments, the stabilizer is glycerol. In some embodiments, the glycerol is at a concentration of about 30% to about 75%. In some embodiments, the glycerol is at a concentration of about 30% to about 70%. In some embodiments, the glycerol is at a concentration of about 30% to about 65%. In some embodiments, the glycerol is at a concentration of about 30% to about 50%. In some embodiments, the glycerol is at a concentration of about 38% to about 42%. In some embodiments, the buffering agent comprises sodium citrate, potassium citrate, citric acid, sodium acetate, acetic acid, sodium phosphate, potassium phosphate, or any combination thereof. In some embodiments, the buffering agent comprises sodium citrate. In some embodiments, sodium citrate is at a concentration of about 0.1% to about 2.0%. In some embodiments, sodium citrate is at a concentration of about 0.1% to about 0.6%. In some embodiments, the alpha-amylase retains at least 90% of its activity at a temperature of 4-40 °C. In some embodiments, the alpha-amylase retains at least 90% of its activity at a temperature of 25-30 °C. In some embodiments, the alpha-amylase retains at least 90% of its activity for 1 year. In some embodiments, the alpha-amylase has a shelf life of at least 1 year. In some embodiments, the alpha-amylase has a shelf life of at least 1 year at 25 °C. In some embodiments, the preservative comprises: potassium sorbate, sodium sorbate, sorbic acid, sodium benzoate, benzoic acid, methyl paraben, calcium propionate, sodium propionate, ammonium propionate, propionic acid, or any combination thereof. In some embodiments, the liquid enzyme formulation comprises at least two preservatives. In some embodiments, the at least two preservatives comprise methyl paraben and potassium sorbate. In some embodiments, the methyl paraben is at a concentration of about 0.0% to about 0.3%. In some embodiments, the methyl paraben is at a concentration of about 0.1%. In some embodiments, the potassium sorbate is at a concentration of about 0.1% to about 0.5%. In some embodiments, the potassium sorbate is at a concentration of about 0.2%. In some embodiments, liquid enzyme formulations comprising: (a) an alpha-amylase having an amino acid sequence that is at least 80% identical to SEQ ID NO: 1; (b) a sodium citrate; (c) a glycerol; and (d) a potassium sorbate, wherein the pH of the enzyme formulation is about pH 6.3-6.7. In some embodiments, liquid enzyme formulations comprising: (a) an alpha-amylase having an amino acid sequence that is at least 80% identical to SEQ ID NO: l ; (b) a sodium citrate and a citric acid; (c) a glycerol; and (d) a potassium sorbate and a methyl paraben, wherein the pH of the enzyme formulation is about pH 6.3-6.7.

[0006] In some embodiments, the alpha-amylase comprises an amino acid sequence having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to any one of the amino acid sequences as set forth in: SEQ ID NO: l, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO: 10, SEQ ID NO: l l, SEQ ID NO: 12, SEQ ID NO: 13, and SEQ ID NO: 14.

[0007] In some embodiments, the liquid enzyme formulation comprises a second enzyme. In some embodiments, the second enzyme is selected from the group consisting of an alpha-amylase, a beta-amylase, a glucoamylase, a protease, a phytase, a pullulanase, a cellulase, a cellobiohydrolase, a beta-glucosidase, an endoglucanase, a mannanase, and any combination thereof.

[0008] Some embodiments disclosed herein provide methods of making a liquid enzyme formulation comprising: (a) providing a composition comprising an alpha-amylase, wherein the composition has a pH value of about 8.0 to about 10.5; (b) adding a stabilizer to the composition comprising the alpha-amylase to obtain a liquid enzyme formulation; and (c) titrating the pH of the liquid enzyme formulation to a range of pH 6.0-8.0.

[0009] In some embodiments, step (c) comprises titrating the pH of the liquid enzyme formulation to a range of pH 6.3-6.7. In some embodiments, the titrating step comprises adding a buffered sodium citrate stock solution to the liquid enzyme formulation. In some embodiments, the buffered sodium citrate stock solution is added to a final concentration of 0.1-2.0%. In some embodiments, the buffered sodium citrate stock solution is added to a final concentration of 0.1-0.6%. In some embodiments, the stabilizer comprises glycerol. In some embodiments, the glycerol is added to a final concentration of 30-75% In some embodiments, the glycerol is added to a final concentration of 30-50%. In some embodiments, the glycerol is added to a final concentration of 38-42%.

[0010] Some embodiments disclosed herein provide uses of a liquid enzyme formulation, comprising: (a) providing a liquid enzyme formulation comprising an alpha- amylase, a buffering agent, a stabilizer, and a preservative, wherein the pH value of the liquid enzyme formulation is about pH 6.0-8.0; (b) providing a starch; and (c) contacting the liquid enzymatic formulation with the starch, thereby hydrolyzing the starch.

[0011] In some embodiments, the pH of the liquid enzyme formulation is about pH 6.3-6.7. In some embodiments, the liquid enzyme formulation is used for the production of a food ingredient, a food product, a fuel, an alcohol, a cleaning product, such as a detergent, a personal care product, such as a cosmetic, an animal feed, a paper, a paper pulp, a paper product, or a starch based product. In some embodiments, the liquid enzyme formulation is used for oil and gas well operations, in another embodiment the oil and gas well operation is enhanced oil recovery.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 shows an exemplary flowchart illustrating a non-limiting embodiment of the formulation process disclosed herein.

[0013] Figure 2 shows enzyme stability of a high pH alpha-amylase enzyme formulation containing methyl paraben (three different production lots) at six months. The alpha-amylase enzyme formulation contains 40% glycerol, 0.1% methyl paraben, and pH 10.7. The samples were stored at 5°C, 22°C, 30°C and 37°C, respectively.

[0014] Figure 3 shows enzyme stability of a high pH alpha-amylase enzyme formulation having no methyl paraben (three different production lots) at six months. The alpha-amylase enzyme formulation contains 40% glycerol, and pH 10.7. Various samples were stored at 5°C, 22°C, 30°C and 37°C, respectively.

[0015] Figures 4A, 4B, & 4C show enzyme stability of an exemplary low pH alpha-amylase (SEQ ID NO: l) enzyme formulation (three different production lots) at six months. The alpha-amylase enzyme formulation contains 40% glycerol, 0.2% potassium sorbate, 0.1% methyl paraben, pH 6.5, and sodium citrate at 5 mM, 10 mM or 20 mM. The samples were stored at 4°C, 25°C and 40°C, respectively.

[0016] Figures 5A & 5C show the comparison of enzyme stability between alpha- amylase enzyme formulations at two different pH (three different production lots) at six months. The high pH alpha-amylase enzyme formulation contains 40% glycerol, 0.1% methyl paraben, and pH 10.7; the low pH alpha-amylase enzyme formulation contains 40% glycerol, 0.1% methyl paraben, 0.2% potassium sorbate, 10 mM sodium citrate, pH 6.5. Each of three enzyme production lots were formulated into the two different formulations. The samples were stored at 4°C, 25°C, 30°C and 40°C, respectively.

[0017] Figures 6 shows the comparison of enzyme stability between alpha- amylase enzyme formulations at two different pH at twelve months. The high pH alpha- amylase enzyme formulation contains 40% glycerol, 0.1% methyl paraben, and pH 10.7; the low pH alpha-amylase enzyme formulation contains 40% glycerol, 0.1% methyl paraben, 0.2% potassium sorbate, 10 mM sodium citrate, pH 6.5. The same enzyme production lot was formulated into the two different formulations. The samples were stored at 4°C, 25°C, 30°C and 40°C, respectively.

[0018] Figures 7A & 7C show the comparison of enzyme stability between two different alpha-amylase enzyme formulations at high pH (three different production lots) at five months. Formulation A contains 40% glycerol, 0.1% methyl paraben, 0.2% potassium sorbate, 10 mM sodium citrate, pH 6.5; formulation B contains 50% glycerol, 0.2% potassium sorbate, 10 mM sodium citrate, pH 6.5. Each of three enzyme production lots were formulated into the two different formulations. The samples were stored at 4°C, 25°C, 30°C and 40°C, respectively.

DETAILED DESCRIPTION

[0019] The current alpha-amylase high pH formulation comprises 40% w/v glycerol, 0.1 % w/v methyl paraben, pH 10.7. The selection of pH 10.7 was the due to limited solubility of the enzyme at lower pH and the process difficulty in titrating the pH down across a wide range after downstream recovery. The high pH formulation does not provide the necessary product stability because it is unbuffered, pH drift which occurs over time poses a risk for subsequent microbial contamination and commercial losses during bulk shipment, warehouse storage, or product storage at industrial plants. The present disclosure provides a liquid enzyme formulation comprising an alpha-amylase formulation that has a neutral or acidic pH for increased stability and shelf life.

Definitions

[0020] The term "liquid enzyme formulation" means to a liquid composition comprising an enzyme. In some embodiments, a liquid enzyme formulation further comprises a buffer, a stabilizer, and a preservative. In some embodiments, the enzyme is an alpha- amylase, a beta-amylase, a glucoamylase, a protease, a phytase, a pullulanase, a cellulase, cellobiohydrolase, a beta-glucosidase, a endoglucanase, a mannanase, a xylanase, or any combination of enzymes thereof.

[0021] An enzyme is a biological molecule comprising a sequence of amino acids, wherein the enzyme can catalyze a reaction. Enzyme names are known to those skilled in the art based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB). Enzyme names include: an EC (Enzyme Commission) number, recommended name, alternative names (if any), catalytic activity, and other factors. Enzymes are also refereed to as a polypeptide, a protein, a peptide, an amino acid sequence, or is identified by a SEQ ID NO. in this disclosure.

[0022] An enzyme is "thermostable" if it retains a substantial amount of its activity after a high temperature treatment of at least about 65°C to about 95°C; or at a temperature greater than 95°C. In some embodiments, the thermostable enzyme retains at least: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% of its enzymatic activity.

[0023] Starch can be any virgin, modified, or degraded starch, or polysaccharide/oligosaccharide. Virgin starches may consist of amylose, amylopectin, or mixtures thereof. Modified starches may comprise oxidized starch, starch esters, or starch ethers. [0024] Types of starch contemplated include virgin starches such as potato starch; wheat starch, corn starch, rice starch, or other grain based starch; or tapioca starch, preferably corn starch. The starches could also be any biomass-containing starch components from plants or agricultural residues. Chemically modified starches may also be used, such as hydroxyethyl or hydroxypropyl starches, or else starches which contain anionic groups, such as phosphate starch, or else cationized starches containing quaternary ammonium groups, preference being given to a degree of substitution DS of 0.01 to 0.2. This degree of substitution DS indicates the number of cationic groups present on average in the starch per glucose unit. Particularly preferred are amphoteric starches, which contain not only quaternary ammonium groups but also anionic groups such as carboxylate and/or phosphate groups, and which may optionally also have undergone chemical modification, having for example been hydroxyalkylated or alkyl-esterified. The starches may be used individually or else in any desired mixtures with one another.

[0025] The starches may be present with other hemicelluloses or polysaccharides, such as but not limited to galactomannans, xylans, arabinoxylans, glucuronoxylans, glucomannans, xyloglucans (such as Tamarind seed flour), pectins/pectate, galactans, arabinogalactans. In the case where starch used contains other polysaccharides, it is optional that hemicellulase enzymes or polysaccharide enzymes may be used in combination with the amylase for the preparations of surface starch composition of the present disclosure. In one option, xylanases (for example: Luminase™ PB-100, Luminase™ PB-200) from BASF can be used. In fact hemicellulases, xylanases, cellulases, and other enzymes from any suppler is implied, including from Novozymes, Dyadic, Dupont, and BASF. If the starchy materials contain proteins and fats, protease and lipases may optionally be used in combination with the aforementioned enzymes comprising amylase.

[0026] The starch used in the present disclosure, preferably, is a native starch, or a substantially un-modified starch. One example is the Pearl starch from Tate and Lyle. However, the starch used can also be any modified or partially modified starches, as modified by thermal treatment, by thermal-mechanical treatment, by acid hydrolysis, by oxidations, by ester derivatizations, (such as starch acetates, starch phosphates), by ether modifications or hydroxyl-alkyl derivatizations (such as hydroxypropyl starches, hydroxyethyl starches or ethylated starches, hydroxypropyl starch phosphates, carboxymethyl starches, various cationic starches, and previously enzyme modified starches, and pre-gelatinized starches. Common examples include industrial starches from A.E. Staley, Penford (Ingredion), Tate and Lyle, ADM, Cargill, Rasio, Roguette, and Amylum, to name a few.

[0027] As used herein, "carbohydrates," "saccharide" or "sugar" refers to a macromolecule consisting of carbon (C), hydrogen (H), and oxygen (O) atoms, usually with a hydrogen: oxygen atom ratio of 2: 1 (as in water); in other words, with the empirical formula Cm(H20)n (where m could be different from n). Polysaccharides can have more than one saccharide and are used for the storage of energy. Monosaccharides contain only one saccharide unit, while a disaccharide can contain two saccharide units, or two joined monosaccharides.

[0028] A "buffering agent" means a weak acid or base used to maintain the acidity (pH) of a solution near a chosen value after the addition of another acid or base.

[0029] A "stabilizer" means a chemical that minimize the instability of an enzyme and therefore maintain its stability. The instability of an enzyme can be due conformational instability, colloidal instability or chemical degradation, which can leads to the loss of enzymatic activity. Examples of stabilizers include but not limited sugars, polyols and salts.

[0030] A "preservative" is an agent that kills microorganisms or inhibits their growth, including disinfectants, antiseptics, and antibiotics, etc.

[0031] The term "comprising" as used herein is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended, which means that additional elements not recited or method steps not recited can be within the scope of this disclosure.

[0032] It is understood that aspects and embodiments of the invention described herein include "consisting" and/or "consisting essentially of aspects and embodiments.

[0033] Throughout this disclosure, various aspects are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0034] Other objects, advantages and features of the present disclosure will become apparent from the following specification taken in conjunction with the accompanying drawings.

[0035] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present disclosure. However, it will be apparent to one of skill in the art that the methods of the present disclosure may be practiced without one or more of these specific details. In other instances, well-known features and procedures well known to those skilled in the art have not been described in order to avoid obscuring the disclosure.

Liquid Enzyme Formulations

[0036] Some embodiments disclosed herein provide liquid enzyme formulations comprising an alpha-amylase and a buffering agent, wherein the pH of the enzyme formulation is about pH 6.0-8.0. In some embodiments, the liquid enzyme formulations comprise a stabilizer. In some embodiments, the liquid enzyme formulations comprise a preservative.

[0037] An enzyme is a biological molecule comprising a sequence of amino acids, wherein the enzyme can catalyze a reaction. Enzyme names are known to those skilled in the art based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB). Enzyme names include: an EC (Enzyme Commission) number, recommended name, alternative names (if any), catalytic activity, and other factors. Enzymes are also known as a polypeptide, a protein, a peptide, an amino acid sequence, or is identified by a SEQ ID NO. In this disclosure, the alternative names for enzyme can be used interchangeably. An "alpha-amylase" is an enzyme that catalyzes the hydrolysis of 1 ,4-alpha-D-glucosidic linkages to degrade polysaccharides, oligosaccharides, and/or starch into glucose subunits. The enzyme classification for an alpha-amylase is EC 3.2.1.1.

[0038] The liquid enzyme formulations disclosed herein may be a pH that is suitable for the stability and maintains the activity of the enzyme contained therein. For example, the pH of the liquid enzyme formulation may be a value that is, is about, is less than, pH 6.0, pH 6.1 , pH 6.2, pH 6.3, pH 6.4, pH 6.5, pH 6.6, pH 6.7, pH 6.8, pH 6.9, pH 7.0, pH 7.1 , pH 7.2, pH 7.3, pH 7.4, pH 7.5, pH 7.6, pH 7.7, pH 7.8, pH 7.9, pH 8.0, or a range that is between any two of the above mentioned values. In some embodiments, the pH of the liquid enzyme formulation is about pH 6.0-7.5, pH 6.0-7.0, pH 6.0-6.7, or pH 6.3-6.7.

[0039] A variety of suitable buffering agents may be used to adjust the pH of the liquid enzyme formulations disclosed herein. For example, the liquid enzyme formulations may comprise a buffering agent selected from the group consisting of: sodium citrate, potassium citrate, citric acid, sodium acetate, acetic acid, sodium phosphate, potassium phosphate, and any combination thereof. In some embodiments, the liquid enzyme formulations comprise a buffering agent that is sodium citrate. The sodium citrate may be included in the liquid enzyme formulations at a concentration that is, is about, is less than, is more than, 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), 0.4% (w/v), 0.5% (w/v), 0.6% (w/v), 0.7% (w/v), 0.8% (w/v), 0.9% (w/v), 1.0% (w/v), 1.1% (w/v), 1.2% (w/v), 1.3% (w/v), 1.4% (w/v), 1.5% (w/v), 1.6% (w/v), 1.7% (w/v), 1.8% (w/v), 1.9% (w/v), 2.0% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the sodium citrate is at a concentration of 0.1-2.0% (w/v) in the liquid enzyme formulation. In some embodiments, the sodium citrate is at a concentration of 0.1 -0.6% (w/v) in the liquid enzyme formulation.

[0040] A variety of suitable stabilizers may be included in the liquid enzyme formulations disclosed herein. For example, the liquid enzyme formulations may comprise a stabilizer such as sucrose, sorbitol, mannitol, glycerol, trehalose, sodium chloride, sodium sulfate, or any combination thereof. In some embodiments, the liquid enzyme formulations comprise a stabilizer that is glycerol. The glycerol may be included in the liquid enzyme formulations at a concentration that is, is about, is less than, is more than, 30% (w/v), 31% (w/v), 32% (w/v), 33% (w/v), 34% (w/v), 35% (w/v), 36% (w/v), 37% (w/v), 38% (w/v), 39% (w/v), 40% (w/v), 41% (w/v), 42% (w/v), 43% (w/v), 44% (w/v), 45% (w/v), 46% (w/v), 47% (w/v), 48% (w/v), 49% (w/v), 50% (w/v), 51% (w/v), 52% (w/v), 53% (w/v), 54% (w/v), 55% (w/v), 56% (w/v), 57% (w/v), 58% (w/v), 59% (w/v), 60% (w/v), 61% (w/v), 62% (w/v), 63% (w/v), 64% (w/v), 65% (w/v), 66% (w/v), 67% (w/v), 68% (w/v), 69% (w/v), 70% (w/v), 71% (w/v), 72% (w/v), 73% (w/v), 74% (w/v), 75% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the glycerol is at a concentration of 30- 75% (w/v) in the liquid enzyme formulation. In some embodiments, the glycerol is at a concentration of 30-70% (w/v) in the liquid enzyme formulation. In some embodiments, the glycerol is at a concentration of 30-65% (w/v) in the liquid enzyme formulation. In some embodiments, the glycerol is at a concentration of 30-50% (w/v) in the liquid enzyme formulation. In some embodiments, the glycerol is at a concentration of 38-42% (w/v) in the liquid enzyme formulation.

[0041] The liquid enzyme formulations disclosed herein have improved stability characteristics. For example, the alpha-amylase of the liquid enzyme formulation disclosed herein can retain its activity at a high percentage, at elevated temperatures, for a long period of time, and thus the liquid enzyme formulation has a longer shelf life. "Shelf life" as used herein refers to how long the liquid enzyme product can be stored at a particular temperature before it begins to lose its enzymatic activity. In some embodiments, the alpha-amylase retains at least 50%, 60%, 70%, 80%, 90%, 95%, or more, of its activity at a temperature, such as 4-40 °C. In some embodiments, the alpha-amylase retains at least 50%, 60%, 70%, 80%, 90%, 95%, or more, of its activity at a temperature of 25-30 °C. In some embodiments, the alpha- amylase retains at least 50%, 60%, 70%, 80%, 90%, 95%, or more, of its activity for 1 year. In some embodiments, the alpha-amylase has a shelf life of at least 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 1 year, or more. In some embodiments, the alpha-amylase has a shelf life of at least 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 1 year, or more, at 25 °C. In some embodiments, the alpha-amylase has a shelf life of at least 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 1 year, or more, at 37 °C.

[0042] As disclosed herein, the liquid enzyme formulations may comprise a variety of preservatives, such as potassium sorbate, sodium sorbate, sorbic acid, sodium benzoate, benzoic acid, methyl paraben, calcium propionate, sodium propionate, ammonium propionate, propionic acid, or any combination thereof. In some embodiments, the liquid enzyme formulations disclosed herein comprise no preservative. In some embodiments, the liquid enzyme formulations disclosed herein comprise only one preservative, such as potassium sorbate. In some embodiments, the liquid enzyme formulations disclosed herein comprise at least two preservatives, such as methyl paraben and potassium sorbate. Methyl paraben may be included in the liquid enzyme formulations at a concentration that is, is about, is less than, is more than, 0.00% (w/v), 0.01% (w/v), 0.02% (w/v), 0.03% (w/v), 0.04% (w/v), 0.05% (w/v), 0.06% (w/v), 0.07% (w/v), 0.08% (w/v), 0.09% (w/v), 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the methyl paraben is at a concentration of 0.05-0.3% (w/v) in the liquid enzyme formulation. In some embodiments, the methyl paraben is at a concentration of 0.1% (w/v) in the liquid enzyme formulation. The potassium sorbate may be included in the liquid enzyme formulations at a concentration that is, is about, is less than, is more than, 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), 0.4% (w/v), 0.5% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the potassium sorbate is at a concentration of 0.1- 0.5% (w/v) in the liquid enzyme formulation. In some embodiments, the potassium sorbate is at a concentration of 0.2% (w/v) in the liquid enzyme formulation.

[0043] In some embodiments, the liquid enzyme formulations may comprise sodium citrate at a concentration of 0.1-2.0% (w/v), glycerol at a concentration of 30-75% (w/v), methyl paraben at a concentration of 0.0-0.3% (w/v), and potassium sorbate at a concentration of 0.1-0.5% (w/v), in the liquid enzyme formulation. In some embodiments, the liquid enzyme formulations may comprise sodium citrate at a concentration of 0.1-0.6% (w/v), glycerol at a concentration of 38-50% (w/v), methyl paraben at a concentration of 0.1% (w/v), and potassium sorbate at a concentration of 0.2% (w/v), in the liquid enzyme formulation.

[0044] Some embodiments disclosed herein provide polypeptides having amylase activities and their uses in the production of a food product, a biofuel, a cleaning product, an animal feed, or a paper pulp, etc., and enhanced oil recovery, etc. In some embodiments, the amylase can be a thermostable alpha amylase, for example a thermostable alpha amylase from bacteria (e.g., Bacillus) or fungi, or any combination (mixture) of enzymes thereof.

[0045] In some embodiments, the alpha amylase comprises or has an amino acid sequence set forth in one of SEQ ID NO: 1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: l l, SEQ ID NO: 12, SEQ ID NO: 13, and SEQ ID NO: 14.

[0046] In some embodiments, the alpha amylase is variant of the parent alpha amylase that comprises or has an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence set forth in any of the following amino acid sequences: SEQ ID NO: l, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO: 10, SEQ ID NO: l l, SEQ ID NO: 12, SEQ ID NO: 13, and SEQ ID NO: 14.

[0047] In some embodiments, the alpha amylase is one of the alpha amylase disclosed in the following patent applications: WO2014007921, WO2011017093, WO2010074999, WO1994019454, WO2010008841, WO2011080352, WO2011080354, WO2011082429, WO 199744361, WO2002068589, WO202068597, WO2002092802, WO2003083054, WO2004091544, WO2009020459, WO2013116175, WO2013148163, WO2008080093, and WO2003018766. The contents of these patent applications are hereby incorporated by reference in their entireties.

[0048] In some embodiments, the alpha amylase is FUELZYME™ (BASF Enzymes LLC, San Diego, CA). Other non-limiting examples of the amylases suitable for use in the methods and compositions disclosed herein include: LpHera® from Novozymes; SPEZYME®XTRA, SPEZYME® CL, SPEZYME® Alpha, SPEZYME® RSL, SPEZYME® FRED, SPEZYME® LT 300, AmyS, AmyL, BAN®480L, Liquozyme® Supra, Liquozyme® SCDS, MAX-LIFE™ PI 00, Maltogenase L, CLARASE® L, Liquozyme® SC, Termamyl® SC, Veretase, Liqozyme® SC4x, Liquozyme® Supra 2.8, Liquozyme® supra 2, Liquozyme® X, Termamyl® 120L, SPEZYME® ALPHA, Clearflow® AA, Optitherm™ and Takatherm™, Keistase™, Avantec.

[0049] In addition to the alpha amylase, the liquid enzyme formulations disclosed herein can include one or more additional enzymes. In some embodiments, the liquid enzyme formulation comprises a second enzyme. In some embodiments, the second enzyme is selected from the group consisting of an alpha-amylase, a beta-amylase, a glucoamylase, a protease, a phytase, a pullulanase, a cellulase, a cellobiohydrolase, a beta-glucosidase, an endoglucanase, a mannanase, and any combination thereof. In some embodiments, the liquid enzyme formulation comprises two or more enzymes. For example, the liquid enzyme formulation can contain the alpha amylase, a second enzyme, and a third enzyme. The third enzyme can be, for example, an alpha-amylase, a beta-amylase, a glucoamylase, a protease, a phytase, a pullulanase, a cellulase, a cellobiohydrolase, a beta-glucosidase, an endoglucanase, a mannanase, or any combination thereof.

[0050] In some embodiments, the liquid enzyme formulations comprise a cellulase or a variant thereof. In some embodiments, the cellulase is any of the cellulases derived from hyperthermophilic bacteria and/or non-naturally occurring variants thereof described in PCT publication WO 2009/020459 (the entire disclosure of which is incorporated herein by reference).

[0051] In some embodiments, the liquid enzyme formulations comprise a beta- glucosidase or a variant thereof. In some embodiments, the beta-glucosidase can be a commercially available product, or any mixture thereof. In some embodiments, the beta- glucosidase can be any of the beta-glucosidases from Thermotoga maritima (BGT), Phanerochaete chrysosporium (BGP), or Aspergillus niger (BG) (Sigma, St. Louis, MO). Methods of Making a Liquid Enzyme Formulation

[0052] Some embodiments disclosed herein provide methods of making a liquid enzyme formulation, wherein the methods comprise titrating the pH of the liquid enzyme formulation to a range of pH 6.0-8.0. In some embodiments, the methods comprise a step of providing a composition comprising an alpha-amylase, wherein the composition has a pH of about pH 8.0-10.5. In some embodiments, the methods comprise a step of adding a stabilizer to the composition comprising alpha-amylase to obtain a liquid enzyme formulation.

[0053] A non-limiting example of the method 100 of making a liquid enzyme formulation in accordance with the embodiments disclosed herein is illustrated in the flow diagram shown in Figure 1. As illustrated in Figure 1, the method 100 can include one or more functions, operations or actions as illustrated by one or more operations 110-160.

[0054] Method 100 can begin at optional operation 110, "Obtaining recovery material." Recovery, often also referred to as downstream recovery, is a process of separating enzyme in the fermentation broth from the expression organism, and the enzyme is potentially further concentrated, purified, refined, washed or buffered exchanged in the solution. Recovery material, sometimes also referred to as enzyme concentrate, contains enzyme in concentrated solution after the recovery process but before the formulation steps. Operation 110 can be followed by operation 120, "Pre-formulation." In this step, a stabilizer may be added to the recovery material, to initially stabilize the enzyme, prior to the additions of other formulation ingredients and additional adjustments to the final formulated product. Operation 120 can be followed by optional operation 130, "Adding preservative to pre-formulation mixture." Operation 130 can be followed by optional operation 140, "Small volume pH titration test." In this test, a stock solution of concentrated acidic buffer at a particular pH is added and mixed to the pre-formulation mixture incrementally, and the pH of the solution is measured. When the pH of the solution reaches the target range of the final formulation, the volume of the stock buffer solution required is recorded. An additional buffer stock solution at a lower pH may be required to repeat the titration test if too much buffer stock volume is used in the initial test. The purpose of this titration test is to determine the precise pH and volume of an acidic buffer stock solution required so that the final formulation solution reaches target pH range within the concentration range of the buffer reagent in the final formulation. In some embodiments, no additional strong acid is used for the pH titration. In some embodiments, a set volume of the buffer stock solution is added to the pre-formulation mixture, and then a strong acid is used to adjust the final pH to the formulation target in the titration test. The exact volumes of the buffer stock solution and acid used are recorded. Operation 140 can be followed by operation 150 "Titrating pH of liquid enzyme formulation." This step may be carried out based on the result from Operation 140. The volume and pH requirements of the acidic buffer stock solution and the strong acid are scaled up to the entire production volume. Operation 150 can be followed by optional operation 160, "Obtaining final formulated liquid product and packaging."

[0055] In Figure 1, operations 110-160 are illustrated as being performed sequentially with operation 110 first and operation 160 last. It will be appreciated, however, that these operations can be combined and/or divided into additional or different operations as appropriate to suit particular embodiments. For example, additional operations can be added before, during or after one or more operations 110-160. In some embodiments, one or more of the operations can be performed at about the same time. In some embodiments, the method only consists of operations 120 and 150, but not any other operations. In some embodiments, the method consists essentially of operations 120 and 150. In some embodiments, the method only consists of operations 120, 150 and one of operations 110, 130, 140 and 160, but not any other operations. In some embodiments, the method only consists of operations 120, 150 and two of operations 110, 130, 140 and 160, but not any other operations. In some embodiments, the method only consists of operations 120, 150 and one or more of operations 110, 130, 140 and 160, but not any other operations.

[0056] At optional operation 110, "Obtaining recovery material," the recovery material is not particularly limited and can be any composition comprising an alpha-amylase. The pH of the recovery material is not particularly limited. For example, the composition comprising an alpha-amylase may have a pH value that is, is about, is less than, is more than, pH 8.0, pH 8.1 , pH 8.2, pH 8.3, pH 8.4, pH 8.5, pH 8.6, pH 8.7, pH 8.8, pH 8.9, pH 9.0, pH 9.1 , pH 9.2, pH 9.3, pH 9.4, pH 9.5, pH 9.6, pH 9.7, pH 9.8, pH 9.9, pH 10.0, pH 10.1 , pH 10.2, pH 10.3, pH 10.4, pH 10.5, or a range that is between any two of the above mentioned values. In some embodiments, the pH of the composition comprising an alpha-amylase may be adjusted to pH 10.0 if needed. In some embodiments, the pH of the composition comprising an alpha-amylase is about pH 8.0-10.5. In some embodiments, the composition comprising an alpha-amylase may have an enzyme activity, e.g., alpha-amylase activity that is at least 300,000 MWU/g (Modified Wohlgemuth Units). In some embodiments, the composition comprising an alpha-amylase may have an enzyme concentration, e.g., alpha-amylase, that is about 300,000 - 400,000 MWU/g.

[0057] At operation 120, "Pre-formulation," a variety of stabilizers may be added to the composition comprising an alpha-amylase. For example, a stabilizer such as sucrose, sorbitol, mannitol, glycerol, trehalose, sodium chloride, sodium sulfate, or any combination thereof, may be added to the composition comprising an alpha-amylase. In some embodiments, glycerol is added to the composition comprising an alpha-amylase as stabilizer. The glycerol may be added to the composition comprising an alpha-amylase to a final concentration that is, is about, is less than, is more than, 30% (w/v), 31% (w/v), 32% (w/v), 33% (w/v), 34% (w/v), 35% (w/v), 36% (w/v), 37% (w/v), 38% (w/v), 39% (w/v), 40% (w/v), 41% (w/v), 42% (w/v), 43% (w/v), 44% (w/v), 45% (w/v), 46% (w/v), 47% (w/v), 48% (w/v), 49% (w/v), 50% (w/v), 51% (w/v), 52% (w/v), 53% (w/v), 54% (w/v), 55% (w/v), 56% (w/v), 57% (w/v), 58% (w/v), 59% (w/v), 60% (w/v), 61% (w/v), 62% (w/v), 63% (w/v), 64% (w/v), 65% (w/v), 66% (w/v), 67% (w/v), 68% (w/v), 69% (w/v), 70% (w/v), 71% (w/v), 72% (w/v), 73% (w/v), 74% (w/v), 75% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the glycerol is added to the composition comprising an alpha-amylase to a final concentration of 30-50% (w/v). In some embodiments, the glycerol is added to the composition comprising an alpha-amylase to a final concentration of 38-42% (w/v).

[0058] At optional operation 130, "Adding preservative to pre-formulation mixture," a variety of preservatives may be added. A preservative such as a potassium sorbate, sodium sorbate, a sorbic acid, a sodium benzoate, a benzoic acid, a methyl paraben, a calcium propionate, a sodium propionate, an ammonium propionate, a propionic acid, or any combination thereof, may be added to the pre-formulation mixture. In some embodiments, no preservative is added to the pre-formulation mixture. In some embodiments, one preservative, added to the pre-formulation mixture. In another embodiment, the one preservative added to the pre-formulation mixture is potassium sorbate. In some embodiments, at least two preservatives, such as methyl paraben and potassium sorbate, can be added to the pre- formulation mixture. The methyl paraben can be added to the pre-formulation mixture to a final concentration that is, is about, is less than, is more than, 0.00% (w/v), 0.01 % (w/v), 0.02% (w/v), 0.03% (w/v), 0.04 % (w/v), 0.05% (w/v), 0.06% (w/v), 0.07% (w/v), 0.08% (w/v), 0.09% (w/v), 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the methyl paraben may be added to the pre-formulation mixture to a final concentration of 0.05-0.3% (w/v). In some embodiments, the methyl paraben may be added to the pre-formulation mixture to a final concentration of 0.1% (w/v). The potassium sorbate may be added to the pre-formulation mixture to a final concentration that is, is about, is less than, is more than, 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), 0.4% (w/v), 0.5% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the potassium sorbate is added to the pre- formulation mixture to a final concentration of 0.1-0.5% (w/v). In some embodiments, the potassium sorbate is added to the pre-formulation mixture to a final concentration of 0.2% (w/v).

[0059] At optional operation 140, "Small volume pH titration test," the pH of the acidic buffer stock solution may be a value that is, is about, is less than, is more than, pH 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or a range that is between any two of the above mentioned values. In some embodiments, the pH of the acidic buffer stock solution is about pH 4.0. In other embodiments, the pH of the acidic buffer stock solution is about pH 3.5. The concentration of the buffer stock solution may be a value that is, is about, is less than, is more than, 5% (w/v), 10% (w/v), 15% (w/v), 20% (w/v), 25% (w/v), 30% (w/v), 35% (w/v), 40% (w/v), or a range that is between any two of the above mentioned values. A variety of suitable strong acid may be used to titrate the pH in the small volume titration test. For example, the pH during the titration test may be titrated using an acid selected from the group consisting of: citric acid, acetic acid, sulfuric acid, phosphoric acid, hydrochloric acid, and any combination thereof. Small volume in this test refers to a sample volume that is convenient and consistent for lab scale titration, solution mixing and pH measurement, for example, 100 milliliters to 1 liter.

[0060] At operation 150, "Titrating pH of liquid enzyme formulation," the pH of the liquid enzyme formulation can vary. For example, the pH of the liquid enzyme formulation may be a value that is, is about, is less than, pH 6.0, pH 6.1 , pH 6.2, pH 6.3, pH 6.4, pH 6.5, pH 6.6, pH 6.7, pH 6.8, pH 6.9, pH 7.0, pH 7.1 , pH 7.2, pH 7.3, pH 7.4, pH 7.5, pH 7.6, pH 7.7, pH 7.8, pH 7.9, pH 8.0, or a range that is between any two of the above mentioned values. In some embodiments, the pH of the liquid enzyme formulation is about pH 6.3-6.7.

[0061] A variety of suitable buffering agents may be used to titrate the pH of the liquid enzyme formulations disclosed herein. For example, the pH of the liquid enzyme formulations may be titrated using a buffering agent selected from the group consisting of: sodium citrate, potassium citrate, citric acid, sodium acetate, acetic acid, sodium phosphate, potassium phosphate, and any combination thereof. In preferred embodiments, the pH of the liquid enzyme formulations may be titrated using a buffering agent that is sodium citrate. The sodium citrate may be added to the liquid enzyme formulations to a final concentration that is, is about, is less than, is more than, 0.1% (w/v), 0.2% (w/v), 0.3% (w/v), 0.4% (w/v), 0.5% (w/v), 0.6% (w/v), 0.7% (w/v), 0.8% (w/v), 0.9% (w/v), 1.0% (w/v), 1.1% (w/v), 1.2% (w/v), 1.3% (w/v), 1.4% (w/v), 1.5% (w/v), 1.6% (w/v), 1.7% (w/v), 1.8% (w/v), 1.9% (w/v), 2.0% (w/v), or a range that is between two of any of the above mentioned values. In some embodiments, the sodium citrate may be added to the liquid enzyme formulations to a final concentration of 0.1-2.0% (w/v). In some embodiments, the sodium citrate may be added to the liquid enzyme formulations to a final concentration of 0.1 -0.6% (w/v). In some embodiments, a buffered sodium citrate stock solution may be used, instead of a strong acid solution (including citric acid), in order to avoid enzyme precipitation. In some embodiments, the buffered sodium citrate stock solution has a pH of about 3.0-5.0.

[0062] At optional operation 160, "Obtaining final formulated liquid product and packaging," the liquid enzyme formulation after pH adjustment is obtained.

Uses of a Liquid Enzyme Formulation [0063] The liquid enzyme formulations disclosed herein can be used in any applications in which the alpha amylase is suitable. Some embodiments disclosed herein provide uses of a liquid enzyme formulation comprising an alpha-amylase, a buffering agent, a stabilizer and a preservative, wherein the pH of the liquid enzyme formulation is about pH 6.0-8.0 for hydrolyzing a starch. In some embodiments, the liquid enzyme formulation is used for the production of a food product, a biofuel, a cleaning product, an animal feed, or a paper pulp. In some embodiments, the liquid enzyme formulation is used for enhanced oil recovery.

EXAMPLES

[0064] The examples which follow illustrate aspects of the present disclosure. The percentages in the examples are by weight, unless otherwise stated.

[0065] In order to facilitate understanding, the specific embodiments are provided to help interpret the technical proposal, that is, these embodiments are only for illustrative purposes, but not in any way to limit the scope of the invention. Unless otherwise specified, embodiments do not indicate the specific conditions, are in accordance with the conventional conditions or the manufacturer's recommended conditions.

Example 1

Preparation of buffered low pH alpha-amylase formulation with strong acid titration

[0066] Recovery material representing product which would be formulated ("concentrate") was obtained and alpha-amylase enzyme activity (MWU/g; MWU, Modified Wohlgemuth Units), pH, and microbial load (CFU/mL; CFU, colony forming units) were determined upon receipt. pH of the concentrate was adjusted to 10.7 if needed. Activity target for the concentrate was >300,000 MWU/g (necessary to meet pre-formulation target of 185,000 MWU/g after addition of 40% w/v glycerol).

[0067] Pre-formulation mixture was prepared by combining concentrate, 40% w/v glycerol, and Dl-water. pH of the pre-formulation mixture was adjusted to 10.7 with IN NaOH. Activity target at pre-formulation step was 185,000 MWU/g.

[0068] Pre-formulation mixture was optionally pasteurized by heating at 70°C for

1 hour.

[0069] To prepare a low pH formulation, 100X citrate phosphate buffer stock solution (326mM citric acid, 436mM Na2HP0 ₄ , 800mM NaOH, pH 6.5) was added to the mixture to IX final concentration (3.3mM citric acid, 4.4mM Na ₂ HP04, 8mM NaOH). Following buffer addition, preservatives were added to 0.1% w/v final concentration each (methyl paraben, added from 25% w/v stock in 100% ethanol; potassium sorbate, added from 25% w/v stock solution in DI water). Additional glycerol was added to the final formulation solution to achieve 40% w/v glycerol concentration. The final pH of the formulation mixture was adjusted to 6.5 with 12% citric acid. To prepare a high pH formulation (unbuffered, pH 10.7), 0.1 % w/v methyl paraben was added to the pre-formulation mixture, and pH was adjusted to 10.7 with IN NaOH. Additional glycerol was added to the final formulation solution to achieve 40% w/v glycerol concentration. Activity target for the final formulation was 160,000 MWU/g.

[0070] In some embodiments, the formulation mixture may be aliquoted in sterile plastic containers (bottles or tubes) and stored at designated temperatures where stability was monitored (-20°C, 5°C, 22°C, 30°C, and 37°C).

[0071] Enzyme activity was monitored using MWU assay, protein quality and integrity were monitored using HPLC/Reverse phase and SDS PAGE, pH and microbial stability were monitored monthly for minimum of three months.

[0072] pH stability was determined by taking an aliquot of formulated material stored at each designated temperature and determining the pH of the solution. Microbial stability was determined by taking an aliquot of formulated material stored at each designated temperature and plating 200 μΐ on 20mm TSA plates (tryptic soy agar, DIFCO Laboratories).

Example 2

Preparation of buffered low pH alpha-amylase formulation containing methyl paraben without strong acid titration

[0073] Recovery material representing product which would be formulated ("concentrate") was obtained and enzyme (alpha-amylase) activity (MWU/g; MWU, Modified Wohlgemuth Units), pH, and microbial load (CFU/mL; CFU, colony forming units) were determined upon receipt. Activity target for the concentrate was >300,000 MWU/g (necessary to meet pre-formulation target of 185,000 MWU/g after addition of 40% w/v glycerol).

[0074] Pre-formulation mixture was prepared by combining concentrate, 40% w/v glycerol, and Dl-water. Activity target at pre-formulation step was 185,000 MWU/g. [0075] Pre-formulation mixture was optionally pasteurized by heating at 70°C for

1 hour.

[0076] To prepare a low pH formulation, preservatives were added to the pre- formulation mixture to final concentrations of 0.1% w/v for methyl paraben (added from 25% w/v stock solution in 100% ethanol or 10% w/v stock solution from mono propylene glycol) and 0.2% potassium sorbate (added from 25% w/v stock solution in DI water). One kilogram of this pre-formulation mixture with preservatives was retrieved. Small volumes of 1 molar sodium citrate buffer stock solution at pH 4.0 were added to the mixture at 1 gram step increment. The mixture was thoroughly mixed and pH was constantly measured. When the mixture pH reached 6.5, the titration test was stopped and the total amount of sodium citrate stock solution added was recorded. Based on the 1 -kilogram pH titration test, the amount of buffer stock solution needed for formulating the entire production volume was calculated. This volume of 1 molar sodium citrate buffer stock solution at pH 4.0 was then added to the entire pre-formulation mixture with preservatives. Additional glycerol was added to the final formulation solution to achieve 40% w/v glycerol concentration. The pH target of the final formulation mixture was 6.5. If additional pH adjustment was needed, 1 molar sodium citrate buffer stock solution at pH 4.0 or 10% sodium hydroxide would be used. Activity target for the final formulation was 160,000 MWU/g.

[0077] The formulation mixture was aliquoted in sterile plastic containers (bottles or tubes) and stored at designated temperatures where stability was monitored (-20°C, 4°C, 25°C, and 40°C).

[0078] Enzyme activity was monitored using MWU assay, protein quality and integrity were monitored using HPLC/Reverse phase and SDS PAGE, pH and microbial stability were monitored monthly for minimum of three months.

[0079] pH stability was determined by taking an aliquot of formulated material stored at each designated temperature and determining the pH of the solution. Microbial stability was determined by taking an aliquot of formulated material stored at each designated temperature and plating 200 μΐ on 20mm TSA plates (tryptic soy agar, DIFCO Laboratories). Example 3

Preparation of buffered low pH alpha-amylase formulation containing no methyl paraben without strong acid titration

[0080] Recovery material representing product which would be formulated ("concentrate") was obtained and enzyme (alpha-amylase) activity (MWU/g; MWU, Modified Wohlgemuth Units), pH, and microbial load (CFU/mL; CFU, colony forming units) were determined upon receipt. Activity target for the concentrate was >325,000 MWU/g (necessary to meet pre-formulation target of 200,000 MWU/g after addition of 40% w/v glycerol).

[0081] Pre-formulation mixture was prepared by combining concentrate, 40% w/v glycerol, and Dl-water. Activity target at pre-formulation step was 200,000 MWU/g.

[0082] Pre-formulation mixture was optionally pasteurized by heating at 70°C for

1 hour.

[0083] To prepare a low pH formulation, a preservative was added to the pre- formulation mixture to final concentrations of 0.2% potassium sorbate (added from 25% w/v stock solution in DI water). One kilogram of this pre-formulation mixture with preservative was retrieved. Small volumes of 1 molar sodium citrate buffer stock solution at pH 4.0 were added to the mixture at 1 gram step increment. The mixture was thoroughly mixed and pH was constantly measured. When the mixture pH reached 6.5, the titration test was stopped and the total amount of sodium citrate stock solution added was recorded. Based on the 1 -kilogram pH titration test, the amount of buffer stock solution needed for formulating the entire production volume was calculated. This volume of 1 molar sodium citrate buffer stock solution at pH 4.0 was then added to the entire pre-formulation mixture with preservative. Additional glycerol was added to the final formulation solution to achieve 50% w/v glycerol concentration. The pH target of the final formulation mixture was 6.5. If additional pH adjustment was needed, 1 molar sodium citrate buffer stock solution at pH 4.0 or 10% sodium hydroxide would be used. Activity target for the final formulation was 160,000 MWU/g.

[0084] The formulation mixture was aliquoted in sterile plastic containers (bottles or tubes) and stored at designated temperatures where stability was monitored (-20°C, 4°C, 25°C, and 40°C). [0085] Enzyme activity was monitored using MWU assay, protein quality and integrity were monitored using HPLC/Reverse phase and SDS PAGE, pH and microbial stability were monitored monthly for minimum of three months.

[0086] pH stability was determined by taking an aliquot of formulated material stored at each designated temperature and determining the pH of the solution. Microbial stability was determined by taking an aliquot of formulated material stored at each designated temperature and plating 200 μΐ on 20mm TSA plates (tryptic soy agar, DIFCO Laboratories).