Modified bio-enzyme preparation for energy-saving enhanced pulping and application of modified bio-enzyme preparation in pretreatment production of semi-viscous paper pulp
By covalently crosslinking and modifying a variety of enzymes with chitosan, a modified biological enzyme preparation was prepared and the preparation was applied in pulp manufacturing, which solved the problems of large amount of enzymes, high cost, low paper strength, long refining time and high energy consumption in pulp manufacturing, and achieved efficient and energy-saving pulping effect.
Patent Information
- Application Number
- CN202510546849.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2025-06-20
AI Technical Summary
In the pulp manufacturing, existing biological enzyme preparations have problems such as large amount of enzymes, high cost, low paper strength, long refining time and high energy consumption.
A modified biological enzyme preparation was prepared by covalently cross-linking and modification of hemicellulase, cellulose binding protein, polysaccharide monooxygenase, endocellulase and chitosan, and the preparation was applied in pretreatment to improve the enzymatic efficiency and refining performance of wood pulp fibers.
It significantly improves the enzymatic efficiency and refining performance of wood pulp fibers, reduces the amount of enzyme and production costs, solves the problems of long refining time and high energy consumption, and has the advantages of energy saving, environmental protection and high efficiency.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical fields of bioenzymes and pulp manufacturing, and particularly to a modified bioenzyme preparation for energy-saving enhanced pulping and its application in the pretreatment for producing semi-viscous pulp. Background Art
[0002] Biotechnology is a modern high-tech. As the most important part of biotechnology, bioenzyme technology has been applied in multiple industries. Bioenzymes are proteins produced by animals, natural plants, and other organic organisms during their life activities, and have the characteristics of high efficiency, specificity, and diversity. A bioenzyme often has the property of degrading a specific high-molecular substance, and can also be used as an environmentally friendly catalyst to promote the reaction rate of chemical reactions. After different bioenzyme modifications, fibers can achieve the purposes of improving pulp whiteness and whiteness stability, improving the water filtration performance of pulp, enhancing pulp strength, and reducing pulping energy consumption.
[0003] Bioenzymes are widely used in the pulp and paper industry, which can improve pulp properties, reduce energy consumption and pollution. However, problems such as high cost of enzyme preparations, poor stability, and insufficient permeability to wood pulp limit their application. Surfactants can change the molecular structure of enzymes, improve their stability and activity, enhance the permeability to wood pulp, thereby improving the enzyme treatment efficiency, improving the pulping environment, and reducing pulping energy consumption. However, there are few reports on the combined application of bioenzymes and surfactants in the field of pulp manufacturing at present, and most of the bioenzyme preparations focus on improving the enzymatic hydrolysis efficiency of pulp, and there is less research on reducing pulping energy consumption and improving paper strength. Summary of the Invention
[0004] The purpose of the present invention is to provide a modified bioenzyme preparation for energy-saving enhanced pulping and its application in the pretreatment for producing semi-viscous pulp to solve the problems existing in the above-mentioned prior art. The present invention covalently cross-links and modifies with a surfactant chitosan and a composite bioenzyme, and after putting it into wood pulp for preliminary pulping treatment, the enzymatic hydrolysis efficiency and pulping performance of wood pulp fibers are significantly improved. It overcomes the defects of large enzyme dosage, high cost, and low paper strength, solves the problems of long pulping time and high energy consumption, and has the advantages of energy saving, environmental protection, and high efficiency.
[0005] To achieve the above purpose, the present invention provides the following scheme:
[0006] The present invention provides a preparation method of a modified bioenzyme preparation for energy-saving enhanced pulping, including the following steps:
[0007] (1) Mix a hemicellulase solution, a cellulose-binding protein solution, a polysaccharide monooxygenase solution, and an endocellulase solution to obtain a composite bioenzyme solution;
[0008] (2) Mix the composite bio - enzyme solution with the chitosan solution, and then add a cross - linker for reaction to obtain the modified bio - enzyme preparation.
[0009] Further, the enzyme activities of the hemicellulase solution, cellulose - binding protein solution, polysaccharide mono - oxygenase solution, and endo - cellulose solution are all 100,000 - 150,000 U / mL; the concentration of the chitosan solution is 100 - 500 mg / L.
[0010] Further, when the hemicellulase solution, cellulose - binding protein solution, polysaccharide mono - oxygenase solution, and endo - cellulose solution are mixed, the volume ratio is 40 - 45:22 - 28:10 - 15:18 - 22; when the composite bio - enzyme solution is mixed with the chitosan solution, the volume ratio is 1:1 - 1.2; the cross - linker is added to a final concentration of 0.5 wt% - 2 wt%.
[0011] Optionally, the cross - linker is glutaraldehyde.
[0012] Further, the temperature of the reaction is 4 - 25 °C, the time is 1 - 2 h, and the pH is 7 - 8.
[0013] Further, after the reaction, a terminator is added to terminate the reaction.
[0014] Optionally, the terminator is glycine with a concentration of 0.1 mol / L.
[0015] The present invention also provides a modified bio - enzyme preparation obtained by the above - mentioned preparation method.
[0016] The present invention also provides the application of the above - mentioned modified bio - enzyme preparation in the pretreatment for producing semi - viscous pulp.
[0017] The present invention also provides an energy - saving and enhancing grinding production method for semi - viscous pulp, comprising the following steps:
[0018] S1. Mix the above - mentioned modified bio - enzyme preparation with wood pulp and conduct preliminary grinding.
[0019] S2. Conduct enzymatic hydrolysis pretreatment on the pulp after preliminary grinding.
[0020] S3. Conduct fine grinding on the pulp after enzymatic hydrolysis pretreatment to obtain the semi - viscous pulp.
[0021] Further, the addition amount of the modified bio - enzyme preparation is 0.005 wt% - 0.01 wt% of the absolute dry pulp of the wood pulp; the pulp concentration of the wood pulp is 35 wt% - 37 wt%.
[0022] Further, the preliminary grinding is carried out using a twin - screw refiner.
[0023] Furthermore, the temperature of the enzymatic pretreatment is 55 - 62°C, the time is 1.5 - 3 h, and the pH is 6 - 7.
[0024] Furthermore, the method for fine grinding is as follows: Adjust the pulp after the enzymatic pretreatment to a pulp consistency of 4 wt% - 8 wt%, and use a two-stage disk refiner for grinding. The gap of the first-stage grinding is set to 0.9 - 1.1 mm, and the gap of the second-stage grinding is set to 0.04 - 0.06 mm; stop grinding when the beating degree reaches 45 ± 2°SR.
[0025] The present invention discloses the following technical effects:
[0026] The present invention uses hemicellulase, cellulose-binding protein, polysaccharide monooxygenase, endocellulase, surfactant, and cross-linking agent to prepare a modified bio-enzyme preparation for energy-saving enhanced grinding, and provides a method for producing pulp by pretreating wood pulp fibers with the modified bio-enzyme preparation. The present invention covalently cross-links and modifies the surfactant and composite bio-enzyme, and combines the high-concentration mixer of the twin-screw refiner for preliminary grinding treatment, which can improve the enzymatic hydrolysis efficiency and grinding performance of wood pulp fibers. It overcomes the defects of large enzyme dosage, high cost, and low paper strength, solves the problems of long grinding time and high energy consumption. This method has the characteristics of energy saving, environmental protection, and high efficiency, responds to the new concept of sustainable development of biomass high-value utilization, and has high promotion value. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0028] Figure 1 It is the process flow chart of Example 2. DETAILED DESCRIPTION OF THE INVENTION
[0029] The various exemplary embodiments of the present invention will be described in detail below. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.
[0030] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.
[0032] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the specification of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.
[0033] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.
[0034] The technical solution of the present invention is realized based on the following principle:
[0035] A composite enzyme system is composed of hemicellulase, cellulose-binding protein, polysaccharide monooxygenase, and endoglucanase. Hemicellulase preferentially degrades xylan in the plant cell wall and decomposes it into smaller xylose molecules, exposing more cellulose. Secondly, cellulose-binding protein binds specifically to the surface of cellulose, helping the enzyme to more effectively locate and attach to the cellulose surface, thereby improving the degradation efficiency of cellulose. Polysaccharide monooxygenase (polysaccharide monooxygenase) focuses on the reaction on the surface of crystalline fibers, activating the surface activity of this part of the fibers and increasing the fiber reaction activity. Endoglucanase randomly cuts the amorphous regions inside the cellulose polysaccharide chain, generating oligosaccharides of different lengths and the ends of new chains, which can effectively promote fiber cutting and swelling. The synergistic effect of multiple enzymes makes the fibrillation degree on the fiber surface higher, thereby avoiding excessive cutting of strong fibers, retaining longer fiber lengths, and improving the folding endurance and tearing strength of the paper.
[0036] Using chitosan-modified bioenzymes to further improve the enzymatic hydrolysis efficiency. First, chitosan, as a natural cationic polysaccharide, can bind to negatively charged components such as cellulose and hemicellulose in wood pulp through electrostatic interactions, changing the surface properties of the wood pulp, increasing the accessibility of the substrate, and making it easier for bioenzymes to approach and act on the substrate. Second, chitosan has good permeability and adsorption properties, effectively penetrating into the internal structure of wood pulp fibers, breaking the hydrophobic barrier on the fiber surface, increasing the wettability of the fibers, and at the same time promoting the adsorption of enzyme molecules on the fiber surface, further improving the catalytic efficiency of the enzyme. In addition, chitosan also has the effect of stabilizing bioenzymes, protecting the active conformation of the enzyme, reducing the inactivation of the enzyme during the reaction, and prolonging the service life of the enzyme. This synergistic effect can not only promote the degradation of wood pulp fibers, but also reduce the enzyme dosage and production costs, and has broad application prospects.
[0037] Shearing, extruding, and friction are applied to the fiber raw materials through two mutually meshing screws, thereby achieving the refinement and uniform dispersion of the fibers. Through the fine treatment of the twin screws, the fiber distribution of the pulp is more uniform, and the physical properties (such as strength, smoothness, etc.) of the pulp are improved.
[0038] Term Explanation:
[0039] "Hemicellulase" refers to an enzyme that can degrade hemicellulose and belongs to the class of glycoside hydrolases. Hemicellulose is a type of polysaccharide substance in plant cell walls other than cellulose, composed of various monosaccharides (such as xylose, arabinose, mannose, galactose, etc.) linked by different glycosidic bonds, and its structure is relatively complex and diverse. Hemicellulase has specific domains that can recognize and bind to hemicellulose molecules. These domains have specific interactions with specific regions or groups of hemicellulose. The active center of hemicellulase contains some key amino acid residues, which catalyze the hydrolysis of glycosidic bonds through an acid-base catalytic mechanism. Taking xylanase as an example, the active center usually has an acidic amino acid residue (such as glutamic acid) and a basic amino acid residue (such as aspartic acid). The acidic amino acid residue provides a proton to protonate the glycosidic bond in the hemicellulose molecule, thereby weakening the stability of the glycosidic bond; the basic amino acid residue helps to stabilize the transition state generated during the reaction and promotes the nucleophilic attack of water molecules on the protonated glycosidic bond, ultimately resulting in the cleavage of the glycosidic bond and the formation of smaller oligosaccharide fragments or monosaccharides.
[0040] "Cellulose-binding protein" refers to a protein that can specifically bind to cellulose. This type of protein has a special domain that can recognize and tightly bind to the surface of cellulose, thereby mediating the interaction between bioenzymes and cellulose, or playing an auxiliary role in the processes of cellulose degradation, modification, etc. Cellulose-binding protein contains a specific cellulose-binding domain (CBD). When the cellulose-binding protein binds to cellulose, related enzymes such as cellulase with a catalytic domain can more effectively approach and bind to the cellulose substrate through interaction with the cellulose-binding protein. This binding increases the local concentration of the enzyme on the substrate surface, improves the affinity between the enzyme and the substrate, and thus promotes the catalytic hydrolysis reaction of the enzyme on cellulose. For example, in the cellulase system of some fungi, the cellulose-binding protein first tightly binds to cellulose, and then the catalytic domain on the cellulase molecule recognizes and approaches the cellulose-binding protein, enabling the cellulase to better act on the β-1,4-glycosidic bond of cellulose. After the cellulose-binding protein binds to cellulose, it may cause conformational changes in the cellulose molecule. Cellulose has a crystalline region and an amorphous region. The crystalline region has a tight structure and is relatively difficult to be acted on by enzymes. After the cellulose-binding protein binds to cellulose, it may break the hydrogen bonds and other interactions between cellulose molecules, making the crystalline structure of cellulose become loose and exposing more amorphous regions. In this way, cellulase with catalytic activity and the like can more easily contact the glycosidic bond of cellulose, thereby improving the accessibility and catalytic efficiency of the enzyme to cellulose.
[0041] "Polysaccharide Monooxygenase" (PMO), also known as cellulose oxidase, is an enzyme that can catalyze the oxidative degradation of complex carbohydrates such as cellulose. This type of enzyme has a unique catalytic mechanism and potential application value. PMOs are metal-dependent enzymes and usually contain copper ions as part of the active center. They can selectively oxidize specific positions (such as carbon 1, carbon 4, or carbon 6 positions) on the cellulose chain in the presence of molecular oxygen, thereby promoting the further degradation of cellulose. This process is different from the way traditional cellulases decompose cellulose through hydrolysis. Instead, it introduces carboxyl groups or other oxygen-containing functional groups through oxidation reactions, making the cellulose structure more easily processed by other enzymes (such as cellulase). The reaction concentrated on the surface of crystalline fibers activates the surface activity of this part of the fibers, increases the fiber reaction activity, and improves the binding force between fibers without breaking down the fibers and causing a decrease in fiber strength; cysteine can eliminate their inhibitory effects and even further activate cellulase.
[0042] "Endoglucanase" refers to endo-1,4-β-D-glucanase (EC 3.2.1.4), which is an important component of the cellulase system and belongs to the glycoside hydrolase family. Endoglucanase has specific domains, and the binding domain among them can recognize and bind to cellulose molecules. Cellulose molecules are linear polysaccharides formed by glucose linked through β-1,4-glycosidic bonds, and there are amorphous regions and crystalline regions in their structures. Endoglucanase prefers to bind to amorphous regions because the cellulose chains in amorphous regions are relatively loose and have higher accessibility. After binding to the substrate, the amino acid residues at the active center of endoglucanase play a role. Generally, its catalytic mechanism follows the acid-base catalysis theory. The active center usually contains an acidic amino acid residue (such as glutamic acid or aspartic acid) and a basic amino acid residue. The acidic amino acid residue provides a proton to protonate the β-1,4-glycosidic bond and make it unstable; the basic amino acid residue plays a role in stabilizing the reaction intermediate and promoting the nucleophilic attack of water molecules. Water molecules attack the protonated glycosidic bond, resulting in the cleavage of the β-1,4-glycosidic bond and generating oligosaccharide fragments at the reducing end and non-reducing end. After the reaction is completed, the generated oligosaccharide products are released from the active center of the enzyme, enabling the enzyme to continue to bind and catalyze the next substrate molecule, thereby achieving the continuous degradation of cellulose.
[0043] The hemicellulase in the following examples of the present invention was purchased from Shanghai Yuanye Bio-Technology Co., Ltd.; the cellulose-binding protein was purchased from Nanjing Novozymes Biotech Co., Ltd.; the polysaccharide monooxygenase was purchased from Beijing Solarbio Science & Technology Co., Ltd.; the endoglucanase was purchased from Shanghai Yuanye Bio-Technology Co., Ltd.; chitosan and glutaraldehyde were both purchased from Shanghai Titan Scientific Co., Ltd.
[0044] Other reagents and drugs involved in the examples of the present invention are all ordinary commercially available products without special instructions; the experimental operations and steps involved in the examples are all carried out according to the conventional operations in the art without special instructions.
[0045] Example 1
[0046] In this example, a highly efficient modified bio-enzyme preparation was prepared, and the preparation process was as follows:
[0047] (1) The hemicellulase, cellulose-binding protein, polysaccharide monooxygenase, and endoglucanase were respectively prepared into 1% solutions using PBS buffer (pH 7.4). The enzyme activity of each solution was 120,000 U / mL.
[0048] (2) The hemicellulase solution, cellulose-binding protein solution, polysaccharide monooxygenase solution, and endoglucanase solution were mixed according to a volume ratio of 43:25:12:20 to obtain a composite bio-enzyme solution.
[0049] (3) Mix the composite bio - enzyme solution with the chitosan solution (200 mg / L) at a volume ratio of 1:1.1. Slowly add glutaraldehyde as the cross - linker under stirring until its final concentration is 1 wt%. Stir the reaction slowly. The pH of the reaction is 7, the temperature is 20 °C, and the reaction time is 1 h. After the reaction is completed, add 2 mL of terminator glycine (concentration 0.1 mol / L) and continue to stir for 30 min to terminate the reaction, obtaining the modified bio - enzyme preparation.
[0050] Example 2
[0051] This example provides a method for producing semi - viscous pulp by modified bio - enzyme pretreatment. The technological process is as Figure 1 shown, and the specific process is as follows:
[0052] 1. Modified bio - enzyme pretreatment of wood pulp fibers
[0053] Prepare wood pulp with a pulp consistency of 35 wt%. Add the modified bio - enzyme preparation of Example 1. The dosage of the modified bio - enzyme preparation is 0.005 wt% of the oven - dry pulp. After mixing and preliminary grinding with a twin - screw refiner, put it into an enzymatic hydrolysis reaction tank for enzymatic hydrolysis pretreatment. The pretreatment conditions are a temperature of 60 °C, a pH value of 7, and a treatment time of 2 h, obtaining the wood pulp slurry after modified bio - enzyme pretreatment.
[0054] 2. Fine grinding of the slurry after enzymatic hydrolysis pretreatment with a two - stage disk refiner
[0055] Adjust the pulp consistency of the pretreated slurry to 8 wt% by adding water. Use two - stage grinding. The gap of the first - stage grinding is set to 1.0 mm, and the gap of the second - stage grinding is set to 0.05 mm. Measure the beating degree of the slurry at different rotational speeds. Stop grinding when the beating degree is controlled at 45 ± 2 o °SR. After the grinding is completed, discharge the pulp and add water to adjust the pulp consistency to 4 wt% for defoaming for 30 min, and directly use it for sheet - making to measure the tensile index of the paper.
[0056] Example 3
[0057] This example provides a method for producing semi - viscous pulp by modified bio - enzyme pretreatment. The specific process is as follows:
[0058] 1. Modified bio - enzyme pretreatment of wood pulp fibers
[0059] Prepare wood pulp with a pulp consistency of 35 wt%. Add the modified bio - enzyme preparation of Example 1. The dosage of the modified bio - enzyme preparation is 0.01 wt% of the oven - dry pulp. After mixing and preliminary grinding with a twin - screw refiner, put it into an enzymatic hydrolysis reaction tank for enzymatic hydrolysis pretreatment. The pretreatment conditions are a temperature of 60 °C, a pH value of 7, and a treatment time of 2 h, obtaining the wood pulp slurry after modified bio - enzyme pretreatment.
[0060] 2. Fine grinding of the slurry after enzymatic hydrolysis pretreatment with a two - stage disk refiner
[0061] The pretreated pulp is adjusted with water to a pulp consistency of 8 wt%, and two-stage beating is adopted. The beating gap in the first stage is set to 1.0 mm, and the beating gap in the second stage is set to 0.05 mm. The beating degree of the pulp is measured at different rotational speeds, and the beating degree is controlled at 45 ± 2 o SR, and then the beating is stopped. After the beating is completed, the pulp is discharged and adjusted with water to a pulp consistency of 4 wt% for 30 min of defoaming, and then directly used for sheet forming, and the tensile index of the paper is measured.
[0062] Comparative Example 1
[0063] The method is the same as that in Example 3; the difference is that no bio-enzyme preparation is added during the pretreatment process of the wood pulp fibers.
[0064] Comparative Example 2
[0065] The method is the same as that in Example 3; the difference is that in the bio-enzyme pretreatment step of the wood pulp fibers, a composite bio-enzyme solution (prepared in step (2) of Example 1) without chitosan cross-linking modification is used.
[0066] Comparative Example 3
[0067] The method is the same as that in Example 3; the difference is that in the bio-enzyme pretreatment step of the wood pulp fibers, the hemicellulase solution and the cellulose-binding protein solution in the components of the modified bio-enzyme preparation are replaced with deionized water (the preparation process of the modified bio-enzyme preparation refers to Example 1).
[0068] Comparative Example 4
[0069] The method is the same as that in Example 3; the difference is that in the bio-enzyme pretreatment step of the wood pulp fibers, the polysaccharide monooxygenase solution and the endocellulase solution in the components of the modified bio-enzyme preparation are replaced with deionized water (the preparation process of the modified bio-enzyme preparation refers to Example 1).
[0070] Test Example 1
[0071] The beating degree and beating energy consumption and other indexes in Example 2, Example 3, and Comparative Examples 1-4 are respectively detected, and the results are shown in Table 1.
[0072] Table 1 Measurement results of beating degree, beating energy consumption, and tensile index of paper for each group
[0073] Experimental parameters Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Example 2 Example 3 Chitosan - - + + + + Enzyme (g / ton) - 100 100 100 50 100 <![CDATA[Beating degree ( o SR)]]> 48±2 50±2 47±2 49±2 49±2 50±2 Energy consumption for pulping (Kw / h·t) 608.47 546.12 382.56 396.78 316.41 275.02 <![CDATA[Tensile index (N·m 2 ·g -1 )]]> 36.37 52.05 55.22 54.13 58.25 63.89
[0074] As can be seen from the data in Table 1, the pulp properties obtained in Example 3 are the best, and the energy consumption of pulp grinding is significantly reduced. When the beating degree reaches 50°SR, the energy consumption of pulp grinding with 0.01% chitosan-modified bio-enzyme preparation pretreatment combined with twin-screw mixing pulp grinding can be reduced to 275.02 Kw / h·t, saving 54.8% of energy consumption compared with Comparative Example 1, 49.6% of energy consumption compared with Comparative Example 2, the tensile index of the paper is increased by more than 75% compared with Comparative Example 1, and the tensile index of the paper is increased by more than 20% compared with Comparative Example 2. It shows that the modified bio-enzyme preparation of the present invention can significantly reduce the energy consumption of pulp grinding and improve the tensile index of the paper, which is beneficial to more efficient production of pulp.
[0075] Example 3 saves 28.11% of energy consumption compared with Comparative Example 3, 30.69% of energy consumption compared with Comparative Example 4, the tensile index of the paper is increased by more than 15% compared with Comparative Example 3, and the tensile index of the paper is increased by more than 18% compared with Comparative Example 4. It shows that the modified bio-enzyme preparation of the present invention utilizes the synergistic effect of multiple enzymes to achieve the technical effects of reducing the energy consumption of pulp grinding and improving the tensile index of the paper. Omitting some of the enzyme preparation will lead to a reduction in the effect.
[0076] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.
Claims
1. A method for preparing a modified bioenzyme preparation for energy saving and enhanced refining, characterized in that: The steps include: (1) mixing a hemicellulase solution, a cellulose binding protein solution, a polysaccharide monooxygenase solution and a cellulose endonuclease solution to obtain a composite biological enzyme solution; (2) After the composite bio-enzyme solution and the chitosan solution are mixed, a cross-linking agent is added to react to obtain the modified bio-enzyme preparation.
2. The preparation method according to claim 1, characterized in that: The enzyme activities of the hemicellulase solution, cellulose binding protein solution, polysaccharide monooxygenase solution and cellulose endonuclease solution are all 100,000-150,000 U / mL; the concentration of the chitosan solution is 100-500 mg / L.
3. The preparation method according to claim 1, characterized in that: The volume ratio of the hemicellulase solution, cellulose binding protein solution, polysaccharide monooxygenase solution and cellulose endonuclease solution when mixed is 40-45:22-28:10-15:18-22; the volume ratio of the composite biological enzyme solution and chitosan solution when mixed is 1:1-1.2; the cross-linking agent is added to a final concentration of 0.5wt%-2wt%.
4. The preparation method according to claim 1, characterized in that: The reaction temperature is 4-25°C, the reaction time is 1-2h, and the pH is 7-8.
5. The modified bioenzyme preparation obtained by the preparation method according to any one of claims 1 to 4.
6. Use of the modified bioenzyme preparation according to claim 5 in pretreatment to produce semi-viscous pulp.
7. A method for producing semi-viscous pulp with energy-saving and enhanced refining, characterized in that: The steps include: S1. Mixing the modified bioenzyme preparation according to claim 5 with wood pulp for preliminary refining; S2, performing enzymatic pretreatment on the pulp after preliminary refining; S3, finely grinding the pulp after enzymatic pretreatment to obtain the semi-viscous pulp.
8. The energy-saving and enhanced pulping production method according to claim 7, characterized in that: The added amount of the modified bio-enzyme preparation is 0.005wt%-0.01wt% of the absolute dry pulp of the wood pulp; the pulp concentration of the wood pulp is 35wt%-37wt%.
9. The energy-saving and enhanced pulping production method according to claim 7, characterized in that: The temperature of the enzymatic pretreatment is 55-62° C., the time is 1.5-3 h, and the pH is 6-7.
10. The energy-saving and enhanced pulping production method according to claim 7, characterized in that: The method for fine refining is: adjusting the pulp after enzymatic pretreatment to a pulp concentration of 4wt%-8wt%, using two-stage disc refiner for refining, with the first stage refining gap set to 0.9-1.1mm and the second stage refining gap set to 0.04-0.06mm; stopping refining when the beating degree is 45±2°SR.