BIO-ENHANCED COMPOSITION FOR IMPROVED BLEACHING AND DE-

LIGNIFICATION OF PULP

FIELD OF INVENTION

The present invention relates to a bio-enhanced composition for improved bleaching and enhanced dehgnification of pulp. More particularly, the present invention relates to a bio- enhanced composition which is essentially free of enzymes and phosphates for improved bleaching and enhanced dehgnification of pulp of the paper industry. Further, the present invention relates to a method of manufacturing the bio-enhanced composition and its use in the dehgnification of pulp at various stages of the multi-stage bleaching process.

BACKGROUND OF INVENTION

Paper pulp is typically processed from raw materials such as wood or agricultural waste through Kraft processes. Process of paper making involves primary steps of delignification wherein pulp is extracted from the raw material followed by two stages of bleaching. During de-lignification and bleaching, chemicals such as chlorine/chlorine dioxide, hydrogen peroxide and caustic soda are used to achieve the necessary whiteness and brightness. A large number of enzyme based methods and other processes are available as a substitute for chemical delignification. However, bleaching still is largely dependent on use of chemicals.

CN 1912239 discloses a two step process for biological bleaching of pulp involving treating the raw pulp with a mixture of white rot fungi, soft rot fungi, brown rot fungi, and black rot fungi along with lime at a concentration of 1.5% in the first step followed by treatment with mycoplasma and 1% hydrogen peroxide. However, this process is cumbersome since the two step process has to be carried out at least thrice to effect bleaching.

ZA9709386 discloses a process to reduce use of soda and peroxide by using Rhodospirillum rubrum at anaerobic or micro aerophilic conditions during the bleaching process. However, this process is effective only for treating silk cotton floss for manufacture of hand-made paper.

Accordingly, there exists a need for a bio-enhanced composition for improved bleaching and enhanced delignification of pulp, which is non-toxic, and essentially free of enzymes and phosphates and reduces the usage of harmful chemicals like chlorine dioxide and hydrogen peroxide.

OBJECT OF THE INVENTION:

One or more of the problems/ limitations of the conventional prior art may be overcome by various embodiment of the present invention.

The primary object of the present invention is to provide a bio-enhanced composition for improved bleaching and enhanced delignification of pulp, which is essentially free of enzymes and phosphates.

It is another object of the present invention is to provide a bio-enhanced composition which is non-toxic and biodegradable. It is another object of the present invention is to provide a bio-enhanced composition which is characterized by Matrix Assisted Laser Desorption/Ionization mass spectroscopy or MALDI-TOF profile and physico-chemical properties.

It is another object of the present invention is to provide a bio-enhanced composition which has pre-defined pH value of 3.11, titratable acidity value ranging from 1.5-1.7%, Emulsifying index or E24 ranging from 85-90% and Hydrophilic-Lipophilic value or HLB value ranging from 16-20. It is another object of the present invention is to provide a bio-enhanced composition which enhances the quality parameters of the pulp, thereby enhancing the economic value proposition. It is another object of the invention to reduce the use of chlorine dioxide by at least 0.9 kg/t and/or hydrogen peroxide by at least 1.0 kg/t and/or sodium hydroxide by at least 1.0 kg/t of pulp to achieve similar or comparable final pulp brightness and improved pulp viscosity as achieved using standard industry procedures. It is another object of the present invention, wherein the bio-enhanced composition for improved bleaching and enhanced delignification of pulp is obtained by fermentation of pre-determined probiotic strains in a medium under pre-defined fermentation conditions.

Another object of the present invention is to provide a method of manufacturing the bio- enhanced composition for improved bleaching and enhanced delignification of pulp.

It is another object of the present invention, wherein the bio-enhanced composition for improved bleaching and enhanced delignification of pulp is used in one or more stages of a multi-stage bleaching and delignification process with conventional bleaching and delignification chemicals or agents.

SUMMARY OF INVENTION

The invention primarily provides a bio-enhanced composition for improved bleaching and enhanced delignification of pulp comprising:

A bio-enhanced composition for bleaching and delignification of pulp comprising:

one or more organic acids;

one or more short chain peptides;

one or more biopolymers; one or more biosurfactants;

one or more polyols;

one or more stabilizers; and

fermentation enhancers or additives,

wherein pH of the bio-enhanced composition is less than 3.11, percent titratable acidity range is 1.5-1.7%,

HLB value range is 16 to 20, and

E24 value range is 85-90%. In another aspect of the invention, the bio-enhanced composition for improved bleaching and enhanced delignification of pulp characterized by MALDI-TOF MS spectra in the m/z range from about 525 m/z to 2345 m/z.

Another aspect of the present invention is to provide a method of manufacturing the bio enhanced composition, comprising:

fermenting a culture medium with at least one starting culture probiotic microorganism; addition of fermentation enhancers or additives to the medium; addition of natural vegetable oils to the medium, wherein the pH of medium is 4.0, resulting in a fermentation product; and

addition of stabilizers to the fermented product,

wherein the emulsifiers or detergents comprises 0.05-0.15% by volume of the culture medium/ broth,

wherein the natural vegetable oils 0.05 to 5% of the total volume of the culture medium/ broth, and

wherein the stabilizers are added at a concentration of 0.5-3% of the total volume of the culture medium/ broth. It is another aspect of the present invention to provide a bio-enhanced composition for bleaching and delignification of pulp comprising wherein the composition is product of fermentation of a culture medium by probiotic microbial consortia. It is another aspect of the present invention to provide a bio-enhanced composition for bleaching and delignification of pulp, wherein the total organic acid content of the composition is 3.4-3.5% w/v of the composition.

It is another aspect of the present invention to provide a bio-enhanced composition for bleaching and delignification of pulp, wherein the total organic acid content comprises 2.0-2.2% by w/v of lactic acid and 1.2-1.4% w/v of acetic acid.

Another aspect of the present invention is directed to compositions resulting from the fermentation of a culture medium or broth and methods using microorganisms preferably probiotic consortia. In particular, the present invention is directed to a composition containing at least 3 microorganisms. At least one microorganism is a sulfide-utilizing microorganism. Additional microorganisms include lactic acid, probiotic, and phototrophic microorganisms, as well as mixtures thereof. Microorganisms may be bacteria, yeast, fungi, or mold species or mixtures thereof. The composition has specific characteristics which are characterized by the MALDI-TOF spectra. The composition is a result of the fermentation on the culture medium which comprises an energy source or the carbon source.

Another aspect of the present invention provides a composition that may include fermentation enhancers or additives. Such enhancers or additives may support growth of microorganisms, induce production of specific metabolites by microorganisms, enhance the stability of the composition, and provide other attributes to the composition of the invention. Suitable additives include a carbon source, acids, and other additives known in the art to support growth, induce specific metabolite production, or stabilize the composition. Examples of such enhancers or additives includes fruit juices, unrefined cane sugar, beet sugar, molasses or natural sugar source, emulsifiers or detergents, natural vegetable oil either alone or in combination with other. In yet another aspect of the present invention, the fermentation of the culture medium by the probiotic consortium is carried out at ambient temperature ranging from about 17° C to about 45° C for a period of 14-42 days.

In yet another aspect, the invention relates to a method of using the bio-enhanced composition comprising adding the bioenhanced composition in an effective amount to the pulp at any of the stages Do, Eop, Di and Ep of a multi-stage bleaching process of the pulp and/or at the Oxygen Delignification stage.

Another aspect of the invention describes how the method reduces the use of chlorine dioxide and/or hydrogen peroxide and/or sodium hydroxide to achieve similar final pulp brightness and improved pulp viscosity.

A more specific aspect of the invention describes how the use of the bio-enhanced preparation reduces the use of chlorine dioxide by at least 0.9 kg/t and/or hydrogen peroxide by at least 1.0 kg/t and/or sodium hydroxide by at least 1.0 kg/t of pulp to achieve similar final pulp brightness and improved pulp viscosity.

In another aspect of the invention, the bio-enhanced composition is used at one or more stages of a multi-stage process of bleaching of pulp along with other conventional chemicals.

BRIEF DESCRIPTION OF THE ACCOMPANYING GRAPHS:

Figure 1 : illustrates the MALDI-TOF profile of bio-enhanced composition according to the present invention. Figure 2: illustrates the flow-chart depicting the process of manufacture of bio-enhanced composition.

DETAILED DESCRIPTION:

The present invention relates to a bio-enhanced composition for improved bleaching and enhanced delignification of pulp which is free of enzymes and reduces the use of chemicals such as chlorine/chlorine dioxide and/or hydrogen peroxide and/or caustic soda used to achieve the necessary whiteness and brightness in the bleaching of the pulp. Further the present invention relates to use of the bio-enhanced composition in one or more stages of a multi-stage bleaching and delignification process of the pulp treatment sequence or process along with conventional bleaching or delignification agents used in the industry. The present invention further relates to a method of manufacturing the bio- enhanced composition. The bio-enhanced composition for improved bleaching and enhanced delignification of pulp further comprises: one or more bio surfactant; one or more polyols; one or more biopolymer; one or more organic acid and one or more small chain peptides. The bio- enhanced composition has a pH value of less than about 3.11, Titratable Acidity % between about 1.5-1.7, HLB value between about 16 to about 20, E24 value between about 85 and about 90.

An embodiment of the present invention discloses a method of manufacturing the bio enhanced composition, comprising:

fermenting the culture medium with at least one starting culture probiotic microorganism; addition of fermentation enhancers or additives to the medium;

addition of natural vegetable oils to the medium, wherein the pH of medium is 4.0, resulting in a fermentation product; addition of stabilizers to the fermented product, wherein the emulsifiers or detergents comprises 0.05-0.15% by volume of the culture medium/ broth,

wherein the natural vegetable oils 0.05 to 5% of the total volume of the culture medium/ broth, and

wherein the stabilizers are added at a concentration of 0.5-3% of the total volume of the culture medium/ broth.

The obtained fermentation broth is the bio-enhanced composition. The fermentation of the culture medium comprises the culture medium as a carbon-source or energy source. Further comprises acids, and other additives known in the art to support growth, induce specific metabolite production, or stabilize the composition. The fermentation occurs by the addition of microbial consortia, preferably probiotic microbial consortia. The culture medium or broth contains atleast 3 microorganisms. At least one microorganism is a sulfide -utilizing microorganism. Additional microorganisms include lactic acid, probiotic, and phototropic microorganisms, as well as mixtures thereof. Microorganisms may be bacteria, Examples of such enhancers or additives includes fruit juices, unrefined cane sugar, beet sugar, molasses or natural sugar source, the emulsifiers or detergents, natural vegetable oil either alone or in combination with other. Specifically comprises a total organic acid content of the composition is 3.4-3.5% by w/v of the composition, acids further comprise of 2.0-2.2% by w/v of lactic acid and 1.2-1.4% w/v of acetic acid. The fermentation is carried out at ambient temperature ranging from about 17° C to about 45° C for a period of 14- 42 days.

The bio-enhanced product thus produced is used in one or more stages of the multi-stage delignification and bleaching process along with conventional delignification and bleaching chemicals. Analytic techniques:

The bio-enhanced composition for improved bleaching and enhanced delignification of pulp is characterized by a MALDI-TOF MS spectra with peak mass value range from about 525 m/z to about 2345 m/z as illustrated in Figure 1.

MALDI-TOF spectrum analysis of the Bio-enhanced composition

a-cyano- 4 hydroxycinnamic acid (CHCA) was used for Matrix-assisted laser desorption/ionization (MALDI) study. Studies were carried out using a Bruker Microflex - LRF model instrument.

Sample Preparation:

• lOmg sample is dissolved in 2ml of water.

• ΙΟμΙ of dissolved sample is mixed with ΙΟμΙ of CHCA matrix solution (TA-50).

• Vortexed & centrifuged for 5 minutes.

• Take Ιμΐ of supernatant solution, spot in MALDI plate.

• Air dry the sample & taken for the analysis.

The MALDI profile is illustrated in Figure 1.

As illustrated in Figure 1 , the bio-enhanced composition has MALDI-TOF MS spectra with peak mass value range from about 525 m/z to about 2345 m/z.

2. Determination of the HLB values

Hydrophile - Lipophile Balance (HLB) values is created by mixing 1.5 ml of emulsifiers with different ratios of Span 80 (HLB = 4) to the bio-enhanced composition in separate tubes as shown in Table 1. 27 ml of distilled water was added to all the tubes to obtain a solution. 1.5 ml of oil whose HLB value is 6 is added to the solution and shaken for 20 seconds. The tubes were incubated for 24 hours and the HLB value was calculated for the unknown sample using the formula: Percent of Span 80 (%) x 4 (HLB of Span 80) + Percent of Product (%) x Product HLB = 6

The Product HLB = (6 - Percent of Span 80 (%) x 4)/ Percent of Product (%)) TABLE- 1

Suppose the stable emulsion is found to be 84%: 16% the HLB value was calculated using the formula

84 % * 4 + 16 % * Product HLB = 6

Product HLB = 6 - (84/100 * 4) / 16/100

Product HLB = 16.5

3. EMULSIFICATION ASSAY (E 24)

A series of test tubes are taken with 4 ml of sample and 4 ml of petrol to obtain a solution. The solution is vortexed for 2 minutes and allowed to stand for 24 hours. The E24 is given as the percentage of height of the emulsified layer (mm) divided by the total height of the liquid column (mm). 3.5 ml of water, 0.5 ml of TritonXlOO and 4 ml of petrol are added to the control tubes.

The average was calculated for the control and the test and the E24 value was calculated from that.

For illustration:

If the average of control was 67.27 and the sample was 56.36

Emulsification assay (E 24) = 100/67.27 * 56.36 = 83.7 4. Titratable Acidity Determination

Titratable acidity is the total organic acid content of given solution. Samples that are to be tested are suitably diluted to a ratio of 1 : 100 (0.5 ml sample in 50 ml of DI water) with de- ionized water. 20 μΐ (2-3 drops) of 1 % phenolphthalein indicator is added to the diluted sample and mixed to obtain a solution. The solution is titrated against 0.1 N Sodium hydroxide (NaOH) until a faint pink colour is obtained. The amount of NaOH consumed was noted and used in the calculations as shown below.

Total titratable acidity -

(ml of NaOH consumed * normality of NaOH )

TA% = *100

(total volume being titrated * dilution factor) ml of NaOH x ml

normality of NaOH 0.1 N

total volume being titrated -> 50 ml

dilution factor -> 10 ²

Titratable acidity with respect to lactic acid

90 is the molecular weight of Lactic acid. An embodiment of the present invention relates to a method of manufacturing the bio- enhanced composition comprises steps of:

at least one starting culture probiotic organism is fermented through a medium, which contains energy source, fermentation enhancers and additives. Emulsifiers or detergents are added to the medium as fermentation enhancers or additives, said emulsifiers or detergents are added in the range of about 0.05 to about 0.15%. Natural vegetable oils are added to the medium once it reaches a pH value of about 4.0 to obtain a fermented product. The natural vegetable oils are added in the range of about 0.05 to about 5% of the total volume of broth. The fermentation is continued until the desired value of pH, titratable acidity, HLB value and E24 values. Stabilizers are added either alone or in combination along with the fermented product; said stabilizers are added at a concentration of about 0.5 to about 3.0% to render the bio-enhanced composition stable with a long shelf life. The fermentation is carried out at ambient temperature ranging from about 17° C to about 45° C for a period of 14- 42 days. By opting to carry out the fermentation at the ambient temperature without any heating or cooling to maintain a constant temperature, the manufacturing process is made environment friendly. Overall, the entire manufacturing process is aimed at reducing the carbon footprint compared to traditional processes used for similar application.

The probiotic organism includes at least one species of microorganisms from lactic acid, probiotic, phototrophic, and sulfide-utilizing microorganism. In another embodiment, the sulphide-utilizing microorganisms are purple non-sulphur bacterial species. Examples of microorganisms include one or more of Bifidobacterium, Lactobacillus, Lactococcus, Bacillus, Saccharomyces, Rhodopseudomonas, and combinations thereof. The energy source, fermentation enhancers or additives include fruit juices, unrefined cane sugar, beet sugar, molasses or natural sugar source, emulsifiers or detergents and the natural vegetable oil. DE-LIGNIFICATION AND BLEACHING OF THE PULP USING THE COMPOSITION OF THE PRESENT INVENTION

The pulp extracted from cooking is first subject to de-lignification. After delignification, the pulp is bleached through a multi stage process. The multi-stage process is exemplified by a DO - Eop - Dl - Ep sequence. The embodiments of the present invention are also applicable to other bleaching sequences used in the industry. The bio-enhanced composition of the present invention is added to one or more of the conventional multi-stage bleaching processes of the industry. The addition of the bio-enhanced composition to the different stages of the multi-stage bleaching process has resulted in bleaching of the pulp with reduced usage of the chemicals. This finds an application to reduce the use of the harmful chemicals and make the process eco-friendly.

In general, the chemicals used for bleaching are Chlorine, Chlorine dioxide, Caustic Soda and Hydrogen Peroxide. As illustrated in the following tables the addition of the bio- enhanced composition of the present invention to any one or more stages of the bleaching process along with the aforesaid chemicals used has resulted in reduced usage of the bleaching chemicals. This is evaluated by the kappa number, Brightness (%) values, and enhanced viscosity, whiteness index (CIE) etc. The bio-enhanced composition has significant impact on the physical properties of the pulp. The studies on Agro residue pulp, and mixed hardwood pulp treated with the optimized concentration of bio-enhanced composition exhibits better physical properties as illustrated in the table 8, table 14, and table 20 respectively. The pulp is subjected to the following steps of processing, delignification followed by a multi-stage bleaching sequence.

Oxygen Delignification (ODL)

Delignification is a process where residual lignin is further removed using oxygen in the presence of NaOH (caustic soda) which is an alkali. The bio-enhanced composition of the present invention when added at the rate of 150 gms per tonne of pulp reduced the use of caustic soda by 2 kg per tonne while delivering similar results as normal or conventional processes.

Efficacy of the bio-enhanced composition of the present invention in reducing the usage of chemicals for delignification of the mixed hardwood mill pulp is illustrated in Table 21. As illustrated using 150 g/t of the bio-enhanced composition in Oxygen-delignification or ODL stage of bleaching followed by bleaching of the pulp using same chemicals resulted in a saving potential of sodium hydroxide by 2.0 kg/t along with improved brightness by 0.8% and whiteness by 1.2 units.

DO Stage of Bleaching

Chlorine Dioxide (C10 ₂ ) is used as the bleaching agent. Addition of 100 gms per tonne of bio-enhanced composition of the present invention at this stage helps in reduction of Chlorine dioxide application by 1 Kg per tonne while delivering similar results as normal or conventional processes.

Eop Stage of Bleaching

This is the second bleaching stage where bleaching is done using Hydrogen Peroxide in the presence of Caustic Soda. Addition of 100 gms per tonne of bio-enhanced composition of the present invention to the pulp helps in reducing Caustic usage by 0.5 to 1.0 kg and Hydrogen Peroxide usage by 0.5 to 1.0 Kg. Dl and Ep stage of bleaching

These are the last 2 stages of bleaching. The bio-enhanced composition of the present invention was not added here and regular bleaching process was followed.

Bleaching efficacy or improved bleaching with reduced usage of the chemicals by the application of bio-enhanced composition to the bleaching process is evaluated mainly by kappa number and Brightness (% ISO). Kappa number estimates the amount of chemicals required during bleaching of wood pulp to obtain a pulp with a given degree of whiteness. Since the amount of bleach needed is related to the lignin content of the pulp, the Kappa number can be used to monitor the effectiveness of the lignin-extraction phase of the pulping process. The effect of the bio-enhanced composition on reducing the usage of chlorine, NaOH or caustic soda is evaluated in terms of reduced Kappa number and increased ISO brightness %.

The efficacy of the bio-enhanced composition is illustrated in detail by the examples and the tables herein.

Examples

Example 1 : Use of bio-enhanced composition for improved bleaching and enhanced delignification of hardwood bamboo mill pulp.

Step 1 : Oxygen De-Lignification (ODL) of pulp was carried out prior to elemental chlorine free (ECF) bleaching of pulp. The ODL of mixed hardwood bamboo mill pulp is given in Table 1.

Table 1 : ODL of mixed hardwood bamboo mill pulp

Bio-enhanced 0 50 100 200

composition (g/TP)

End pH 2.5 2.3 2.4 2.4

Residual C10 ₂ (ppm) 12.4 12.1 18.1 20.8

EOP stage (Cy - 10.0%, NaOH - 1.05%, H ₂ 0 ₂ - 0.50%, Temp. - 80°C,

Time - 120 Min., 0 ₂ - 0.6%)

End pH 10.6 10.7 10.6 10.6

Residual H ₂ 0 ₂ (ppm) 31.0 41.0 46.3 45.4

Kappa no. 1.9 1.7 1.6 1.7

Brightness (% ISO) 80.3 80.9 81.4 81.3

Step 2: The bio-enhanced composition was used in Do stage of bleaching. Different concentrations of bio-enhanced composition were used to optimize its dosage. The Optimization of bio-enhanced composition dose in Do stage of bleaching is given in Table 2.

Table 2: Optimization of bio-enhanced composition dose in Do stage of bleaching

Shrinkage (%) 3.7

It was observed that based on kappa reduction and brightness developed after Eop stage of bleaching, the bio-enhanced composition dose of 100 g/t was considered as optimum for Do stage of bleaching. With the use of lOOg/t bio-enhanced composition in Do stage of bleaching, Eop stage pulp brightness was improved by 1.1 points and kappa number of the pulp reduced by 16%.

Step 3: Optimization of C10 ₂ dose in Do stage using optimized dose of bio-enhanced composition, and the results are given in Table 3.

Table 3: Optimization of C10 ₂ dose in Do stage using optimized dose of bio-enhanced composition

It was observed that with the use of lOOg/t bio-enhanced composition in Do stage bleaching there is saving potential of chlorine dioxide by 0.9 kg/t.

Step 4: Optimization of bio-enhanced composition dose in Di stage of bleaching, and results are given in Table 4.

Table 4: Optimization of bio-enhanced composition dose in Di stage of bleaching

Residual H ₂ 0 ₂ (ppm) 71.4 77.3 75.4 73.4

Brightness (% ISO) 88.9 89.4 89.2 89.0

Whiteness (CIE) 80.9 82.0 81.8 81.0

It was observed that based the brightness developed after Di stage of bleaching, the bio- enhanced composition dose of 50 g/t was considered as optimum. Step 5: Optimization of C10 ₂ dose in Di stage using optimized dose of the bio-enhanced composition, and the results are given in Table 5.

Table 5: Optimization of C10 ₂ dose in Di stage using optimized dose of the bio-enhanced composition.

(g TP)

cio ₂ (%) 0.50 0.50 0.45 0.40

End pH 3.7 3.6 3.6 3.7

Residual C10 ₂ 18.7 19.9 15.5 7.1

(ppm)

Brightness (% 85.7 87.0 85.9 84.8

ISO)

Ep stage (Cy - 10.0%, NaOH - 0.80%, H ₂ 0 ₂ - 0.5%, Temp. - 75°C,

Time - 180 Min.)

Bio-enhanced 0 50

composition

(g/TP)

End pH 10.2 10.3 10.2 10.4

Residual H ₂ 0 ₂ 72.0 75.8 68.0 62.9

(ppm)

Brightness (% 88.9 89.5 89.0 87.4

ISO)

Whiteness (CIE) 80.9 82.0 81.1 78.2

It was observed that with the use of 50 g/t dose of the bio-enhanced composition in Di stage of bleaching, there is potential to reduce 0.5 kg/t chlorine dioxide without compromising the optical properties of pulp.

Step 6: Bulk bleaching of pulp using optimized dosages of chemicals, and the results are given in Table 6.

Table 6: Bulk bleaching of pulp using optimized dosages of chemicals

Do stage (Kappa factor - 0.24, Cy - 10.0%, Temp. - 55°C, Time - 45 Min.)

Bio-enhanced

0 100

composition (g/TP)

C10 ₂ added (%) 0.89 0.89 0.80

End pH 2.4 2.6 2.5

Residual C10 ₂ (ppm) 12.2 17.0 8.1

E ₀ p stage (Cy - 10.0%, Temp. - 80° C, Time - 120 Min., 0 ₂ - 0.6%)

Bio-enhanced

0 100

composition (g/TP)

NaOH added (%) 1.05 1.05 0.95

H ₂ 0 ₂ added (%) 0.50 0.50 0.40

End pH 10.6 10.5 10.1

Residual H ₂ 0 ₂ (ppm) 31.3 27.0 15.7

Kappa no. 1.9 1.6 1.8

Brightness (% ISO) 80.3 81.8 80.1

Di stage (Cy - 10.0%, C10 ₂ - 0.5%Temp. - 75°C, Time - 180 Min.)

Bio-enhanced

0 50

composition (g/TP)

End pH 3.7 3.6 3.6

Residual C10 ₂ (ppm) 18.7 19.7 15.6

Brightness (% ISO) 85.6 87.0 85.7

Ep stage (Cy - 10.0%, NaOH - 0.80%, H ₂ 0 ₂ - 0.5%, Temp. - 75° C, Time - 180 Min.)

Bio-enhanced

0 50

composition (g/TP)

End pH 10.5 10.5 10.4

Residual H ₂ 0 ₂ (ppm) 74.1 77.4 62.1

Brightness (% ISO) 88.9 89.6 89.0 Whiteness (CIE) 80.9 82.0 81.1

Viscosity (cP) 11.7 13.0 13.2

P.C.No. 0.16 0.11 0.14

It was observed that with the use of optimized dosages of bio-enhanced composition in Do, Eop, Di and Ep stages of bleaching there is saving potential of chlorine dioxide by 0.9 kg/t, hydrogen peroxide by 1.0 kg/t and sodium hydroxide by 1.0 kg/t of pulp to achieve similar final pulp brightness and improved pulp viscosity.

Step 7: Analysis of effluent generated during bleaching and the results are given in Table

7.

Table 7: Analysis of effluent generated during bleaching

Step 8: Analysis of Physical strength properties of bleached pulp control and pulps treated with optimized dosage of Bio-enhanced product and the results are given in Table 8.

Table 8: Physical strength properties of bleached pulp control and pulps treated with optimized dosage of Bio-enhanced product Bio-enhanced treatment

Parameter Control Same bleaching Reduced bleaching

chemicals chemicals

Bleaching sequence CEopHiH ₂ CEopHiH ₂ CEopHiH ₂

No. of revolutions 150 150 150

CSF(ml) 435 425 430

°SR 29.5 30.0 30.0

Bulk (cc/g) 1.51 1.51 1.50

Tensile index (Nm/g) 48.1 49.2 49.5

Burst index (kNm ² /g) 3.04 3.10 3.40

Tear index (mNm /g) 5.63 5.82 6.30

Double fold 41 40 47

Example 2: Use of bio-enhanced composition for improved bleaching and enhanced delignification of agro residue and mixed hardwood pulp. A. Study on agro residue pulp

Table 9: Properties of unbleached agro pulp

Table 10: Optimization of Bio-enhanced composition dose in C stage of bleaching

composition (g/TP)

Cl ₂ added (%) 3.35

End pH 2.1 2.1 2.0 2.1

Residual Cl ₂ (%) 30.2 28.4 23.1 19.5

E _OP stage (Cy - 10.0%, Temp. - 70°C, Time - 120 Min, NaOH - 2.2%, H ₂ O ₂ - 0.5%, O ₂ - 0.6%)

End pH 10.0 10.0 10.1 10.2

Residual H ₂ 0 ₂

10.2 10.2 6.8 3.4

(ppm)

Kappa No. 1.1 1.0 0.9 1.0

Brightness (% ISO) 76.7 76.9 78.0 77.8

Observations: Based on kappa reduction and brightness developed after Eop stage of bleaching, Bio-enhanced composition dose of 100 g/t was considered as optimum for C stage of bleaching. With the use of 100 g/t Bio-enhanced composition in C stage of bleaching, Eop stage pulp brightness was improved by 1.3 point and kappa number of the pulp reduced by 18.2%.

Table 11 : Optimization of Bio-enhanced composition dose in Eop stage of bleaching

composition

(g/TP)

End pH 10.0 10.1 10.3 10.4

Residual H ₂ 0 ₂

10.2 10.2 6.8 6.8

(ppm)

Kappa No. 1.1 1.0 0.9 1.0

Brightness (%

76.8 77.1 78.4 78.2

ISO)

Observations: With the use of 100 g/t Bio-enhanced composition in Eop stage of bleaching, kappa number reduced by 18.2% and brightness increased by 1.6 points. Table 12: Bulk bleaching of agro mill pulp with optimized dosages of Bio-enhanced composition

(ppm)

Kappa No. 1.1 0.9 1.0

Brightness (% ISO) 76.8 78.3 77.9

Hi stage (Cy - 10.0%, hypo - 0.80%, Temp. - 45°C, Time - 120 Min.)

Bio-enhanced

0 50

composition (g/TP)

End pH 7.7 7.8 7.9

Residual Cl ₂ (ppm) 26.9 29.8 18.4

Brightness (% ISO) 83.6 84.2 83.8

H ₂ stage (Cy - 10.0%, Hypo - 0.3%, Temp. - 45°C, Time - 120 Min.)

Bio-enhanced

0 50

composition (g/TP)

End pH 8.0 8.1 8.0

Residual Cl ₂ (ppm) 21.5 20.8 16.5

Brightness (% ISO) 84.2 85.1 84.8

Whiteness (CIE) 75.8 77.1 76.1

P. C. number 2.63 2.21 2.21

Viscosity (cP) 10.6 11.3 12.0

Observations: With the use of 100, 50 and 50 g/t Bio-enhanced composition in Eop, Hi and H ₂ stages, respectively, there is saving potential of hydrogen peroxide by 1.0 kg/t and sodium hydroxide by 1.5 kg/t of pulp to achieve similar final pulp brightness and improved pulp viscosity.

Table 13: Analysis of effluent generated during bleaching of agro pulp

TSS (mg/1) 308 291 286

Total solids (mg/1) 3250 3245 3185

TDS (mg/1) 2942 2954 2899

COD (mg/1) 1129 1064 990

BOD (mg/1) 268 254 248

Color (PCU) 1209 1180 1070

AOX (mg/1) 58.6 58.2 56.9

SAR 5.12 5.03 4.65

Observations: With the use of 100, 50 and 50 g/t Bio-enhanced composition in Eop, Hi and H ₂ stages, respectively, and using reduced bleaching chemicals, generation of pollutants viz. COD, BOD and AOX were reduced marginally.

Table 14: Physical strength properties of bleached control and pulps treated with optimized dosage of Bio-enhanced composition

Observations: With the use of 100, 50 and 50 g/t Bio-enhanced composition in Eop, Hi and ¾ stages, respectively, and using reduced bleaching chemicals, physical strength properties of paper improved. B. Study on mixed hardwood pulp

Table 15: Optimization of Bio-enhanced composition dose in oxygen delignification (ODL) stage

Based on kappa reduction and brightness developed after ODL stage of bleaching, Bio- enhanced composition dose of 100 g/t was considered as optimum for ODL stage of bleaching. With the use of 100 g/t Bio-enhanced composition in ODL stage of bleaching, pulp brightness was improved by 13.1 point and kappa number of the pulp reduced by 45.9% as compared to control 12.3 and 43.5%, respectively. Table 16: Optimization of Bio-enhanced composition dose in Do stage of bleaching

Observations: Based on the earlier work carried out, 0.24 the kappa factor was used in Do stage of bleaching. Based on kappa reduction and brightness developed in Eop stage after using different dosages of Bio-enhanced composition in Do stage of bleaching, Bio- enhanced composition dose of 100 g/t was considered as optimum for Do stage of bleaching.

Table 17: Optimization of Bio-enhanced composition dose in EQ _P stage of bleaching

End pH 2.4

Residual C10 ₂ (ppm) 16.4

E _0P stage (Cy - 10.0%, NaOH - 0.98%, H ₂ 0 ₂ - 0.50%, Temp. - 80°C,

Time - 120 Min., 0 ₂ - 0.6%)

Bio-enhanced

0 50 100 200

composition (g/TP)

End pH 10.6 10.6 10.9 11.0

Residual H ₂ 0 ₂ (ppm) 21.9 16.3 10.2 6.8

Kappa no. 1.5 1.4 1.3 1.3

Brightness (% ISO) 81.6 82.1 83.0 82.9

Observations: With the use of 100 g/t Bio-enhanced composition in Eop stage of bleaching, kappa number reduced by 13.3% and brightness increased by 1.1 points while using similar bleaching chemicals.

Table 18: Bulk bleaching of pulps using optimized dosages of chemicals

composition (g/TP)

NaOH added (%) 0.98 0.98 0.88

H ₂ 0 ₂ added (%) 0.50 0.50 0.40

End pH 10.6 10.7 10.5

Residual H ₂ 0 ₂ (ppm) 21.9 16.3 10.2

Kappa no. 1.5 1.3 1.7

Brightness (% ISO) 81.7 83.0 81.6

Di stage (Cy - 10.0%, C10 ₂ - 0.5% Temp. - 75°C, Time - 180 Min.)

Bio-enhanced

50

composition (g/TP)

End pH 3.4 3.4 3.3

Residual C10 ₂ (ppm) 5.4 5.4 Nil

Brightness (% ISO) 87.1 87.9 86.8

Ep stage (Cy - 10.0%, NaOH - 0.50%, H ₂ 0 ₂ - 0.3%, Temp. - 75°C, Time

- 180 Min.)

Bio-enhanced

50

composition (g/TP)

End pH 10.2 10.2 10.3

Residual H ₂ 0 ₂ (ppm) 104.1 97.3 76.9

Brightness (% ISO) 88.6 89.5 88.5

Whiteness (CIE) 80.9 82.3 80.7

Viscosity (cP) 12.5 13.7 14.5

RC. No. 0.19 0.18 0.18

Observations: With the use of 100 g/t Bio-enhanced composition in Do and Eop stage of bleaching there is saving potential of chlorine dioxide by 1.0 kg/t, hydrogen peroxide by 1.0 kg/t and sodium hydroxide by 1.0kg/t of pulp to achieve similar final pulp brightness and improved pulp viscosity. Table 19: Analysis of effluent generated during bleaching of hardwood pulp

Observations:

With the use of 100, 100, 50 and 50 g/t Bio-enhanced composition in Do, Eop, Di and Ep stages, respectively, and using reduced bleaching chemicals, generation of pollutants viz. COD, BOD and AOX were reduced marginally.

Table 20: Physical strength properties of bleached pulp control and pulps treated with optimized dosage of Bio-enhanced composition

Burst index (kNm ² /g) 3.35 3.72 4.22

Tear index (mNm /g) 8.1 8.3 8.4

Double fold 86 92 95

Table 21: Efficacy of Bio-enhanced composition in Oxygen-delignification stage or ODL stage of mixed hardwood pulp bleaching

NaOH added

0.99 0.97 0.88 0.98

(%)

H ₂ 0 ₂ added (%) 0.5 0.5 0.4 0.5

End Ph 10.9 10.8 10.6 10.8

Kappa no. 1.5 1.3 1.7 1.3

Brightness

81.5 82.4 81.3 82.2

(%ISO)

Dx stage (Cy - 10.0%, C10 ₂ - 0.5% Temp. - 75°C, Time - 180 Min.)

Bio-enhanced

composition 0 50

(g/TP)

End Ph 4.1 4.2 4.0 4.1

Brightness

87.2 88.7 86.9 87.7

(%ISO)

Ep stage (Cy - 10.0%, NaOH - 0.50%, H ₂ 0 ₂ - 0.3%, Temp. - 75°C, Time - 180

Min.)

Bio-enhanced

composition 0 50

(g/TP)

End Ph 10.0 10.1 10.1 10.1

Brightness

88.5 89.4 88.9 89.3

(%ISO)

Whiteness (CIE) 80.8 82.2 80.8 82.0

Viscosity (cP) 13.3 13.6 14.3 14.4

P.C. No. 0.22 0.20 0.22 0.22

Observations: With the use of 150 g/t of the bio-enhanced composition in the oxygen- delignification stage or ODL stage of bleaching followed by bleaching of the pulp using same chemicals there is saving potential of sodium hydroxide by 2.0 kg/t along with improved brightness by 0.8% and whiteness by 1.2 units. With the use of 100 g/t of the bio-enhanced composition in Do and Eop stage of bleaching there is saving potential of chlorine dioxide by 1.0 kg/t, hydrogen peroxide by 1.0 kg/t and sodium hydroxide by 1.1 kg/t of pulp to achieve similar final pulp brightness and improved pulp viscosity.

The use of Bio-enhanced composition and using reduced bleaching chemicals during bleaching of pulp, physical strength properties of paper improved marginally. As illustrated in table 20 treatment of the pulp with bio-enhanced composition of the present invention exhibited comparable results without compromising on the strength and physical properties along with reduced usage of the chemicals.

The above examples provide illustrative representations of the effectiveness of the bio enhanced composition for improved bleaching and enhanced dehgnification and delignification of pulp within the scope of the present invention. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.