A composite bio-enzyme assisted low-energy consumption pulping method

Abstract

The present application relates to the technical field of pulping and papermaking, and provides a composite biological enzyme assisted low-energy consumption pulping method.The method comprises the following steps: S100, pretreating raw materials, adding a composite biological enzyme preparation and a softening agent, and performing softening treatment to obtain a mixture; S200, mechanically pulping the mixture, performing filament separation treatment through a rubbing equipment, and forming a pulp liquid; S300, performing bleaching treatment and cleaning treatment on the pulp liquid, and completing the pulping process; wherein the composite biological enzyme preparation comprises laccase, cellulase, xylanase, pectinase and magnetic particles.The composite biological enzyme preparation can reduce the energy consumption in the pulping process, helps to reduce the production cost, improves the production efficiency, replaces the traditional chemical agent with the composite biological enzyme preparation, reduces the environmental pollution, effectively improves the decomposition rate of plant fibers, makes the pulp more easily obtained, and improves the utilization rate of raw materials.

Description

Technical Field

[0001] This invention relates to the field of pulp and paper technology, and more specifically, to a low-energy pulping method assisted by a composite bio-enzyme. Background Technology

[0002] Papermaking production consists of two basic processes: pulping and papermaking. Papermaking involves combining pulp fibers suspended in water through various processes to form paper sheets that meet various requirements. Biopulping is one of the technological directions for cleaning agent pulp. Biopulping produces pulp fibers that are long, have a high yield, and are highly durable. Moreover, the cost per ton of pulp is significantly lower than that of chemical and mechanical pulp. However, due to the high requirements for the cultivation and selection of biological strains and the conditions of the pulping process, there are many problems such as large production fluctuations, uneven material processing, excessively long processing times, and low production efficiency. Currently, biopulping is still difficult to achieve industrial-scale production.

[0003] Traditional mechanical pulping methods typically require a large amount of energy, leading to high production costs. Energy consumption not only affects economic efficiency but also increases the burden on the environment. At the same time, the pulping process is slow, and the efficiency of enzymatic hydrolysis and mechanical processing is not high, which affects the overall production efficiency. Summary of the Invention

[0004] Therefore, this invention provides a low-energy pulping method assisted by a composite bio-enzyme, aiming to solve the problems of high energy consumption and low efficiency in traditional pulping processes. By using composite bio-enzymes such as laccase, cellulase, and pectinase, and by using ultrasound during enzymatic hydrolysis, the activity and hydrolysis efficiency of the enzymes can be improved, thereby enhancing the hydrolysis efficiency of the raw materials and reducing energy consumption. At the same time, different enzymes are processed and cross-linked in steps to ensure that each enzyme reacts under optimal conditions, thereby increasing reaction efficiency.

[0005] This invention provides a low-energy pulping method assisted by a composite biological enzyme, the method comprising:

[0006] S100: The raw materials are pretreated, and then a compound biological enzyme preparation and a softener are added. The mixture is then enzymatically hydrolyzed under ultrasound to obtain a mixture. S200: The mixture is mechanically pulped and then separated into fibers using a grinding device to form a slurry. S300: The slurry is bleached and washed to complete the pulping process. The compound biological enzyme preparation includes laccase, cellulase, pectinase, and magnetic particles.

[0007] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: The composite bio-enzyme-assisted low-energy pulping method of the present invention utilizes bio-enzymes to partially degrade plant cellulose and hemicellulose, which can reduce energy consumption in the subsequent mechanical pulping process, making the raw materials softer and reducing the power and energy consumption required during grinding; at the same time, the use of composite bio-enzymes helps to preserve fiber structure, reduce fiber damage, and maintain fiber strength. The fibers treated by enzymatic hydrolysis can be separated more evenly during the fiber separation process, thereby improving the quality of the final pulp; in the bleaching step S300, due to the change in the structure of the raw materials after enzymatic hydrolysis, the bleaching treatment is more efficient. This method increases efficiency, reduces the amount of bleaching chemicals required, and improves the bleaching effect, resulting in a whiter and brighter pulp. Furthermore, the application of bio-enzymes reduces reliance on energy-intensive equipment such as high-temperature and high-pressure systems, decreases the use of chemical bleaching agents, and thus reduces harmful chemicals in wastewater, resulting in excellent environmental benefits. In summary, the use of ultrasonic enzymatic hydrolysis and magnetic particle-assisted technologies accelerates enzyme activity, shortens processing time, and improves overall pulping efficiency, helping to reduce production costs. It achieves low-energy production while ensuring pulp fiber quality, and is highly environmentally friendly, meeting the demands of modern green production.

[0008] In one technical solution of the present invention, in step S100, the preparation method of the composite biological enzyme preparation includes: S110: dispersing laccase in a phosphate buffer solution, adding magnetic particles, performing a first stirring treatment, adding a cross-linking agent, and washing with phosphate buffer after the reaction is completed to obtain a first solvent; S120: dispersing cellulase in a phosphate buffer solution, adding the first solvent, performing a second stirring treatment, adding a cross-linking agent, and washing with phosphate buffer after the reaction is completed to obtain a second solvent; S130: dispersing pectinase in a phosphate buffer solution, adding the second solvent, performing a third stirring treatment, adding a cross-linking agent, and washing with phosphate buffer after the reaction is completed to obtain a third solvent; S140: washing the third solvent clean with phosphate buffer to obtain the composite biological enzyme preparation.

[0009] Compared with existing technologies, the technical effects achieved by this solution are as follows: The preparation method of the composite bio-enzyme preparation adopts a layered fixation technology, which gradually disperses and fixes different types of enzymes on magnetic particles to form a composite bio-enzyme preparation with a layered structure. This separates different enzymes, reduces direct contact between them, avoids possible mutual inhibition or incompatibility, and ensures the activity stability of each enzyme. In particular, it effectively reduces the enzyme activity loss that may be caused by interactions between laccase, cellulase, and pectinase. Layered fixation can decompose different raw material components in the required order. Laccase decomposes lignin to expose cellulose, and then cellulase further decomposes lignin. This product acts on cellulose, with pectinase treating pectin components. The synergistic effect of the three enzymes effectively improves the raw material decomposition efficiency, ensuring that each enzyme plays its maximum role in its specific decomposition task and improving the overall enzymatic hydrolysis efficiency. Magnetic particles immobilize each enzyme layer, reducing enzyme loss and providing physical support to each layer, making it less likely for the enzymes to detach from the composite system during processing, thus improving its stability and durability. Furthermore, the layered immobilized composite enzyme is magnetic, allowing for rapid recovery of the enzyme preparation from the slurry after pulping using an external magnetic field. This reduces enzyme consumption during pulping, enabling the enzyme preparation to be recycled multiple times, thereby lowering costs.

[0010] On the other hand, the cross-linking agent enables the formation of cross-linked structures between laccase, cellulase, and pectinase molecules, which helps improve enzyme stability and avoids activity reduction caused by factors such as high temperature and pH changes. This treatment prolongs the enzyme's reaction time, improving its activity and utilization efficiency in the low-energy pulping process. By controlling the pH with phosphate buffer at each step and through multiple washing and stirring processes, the uniform distribution of each enzyme and the purity of the preparation are ensured, resulting in more uniform enzyme contact with the raw materials and effectively improving enzymatic hydrolysis efficiency. This allows for faster fiber processing and ensures optimal activity of the prepared composite enzyme preparation in the low-energy pulping process.

[0011] In one embodiment of the present invention, in step S110, the concentration of laccase is between 6.0 g / L and 7.0 g / L; and / or in step S110, the first stirring temperature is between 3°C and 6°C; and / or in step S120, the concentration of cellulose is between 1.0 g / L and 5.0 g / L; and / or in step S120, the second stirring temperature is between 20°C and 25°C; and / or in step S130, the concentration of pectin is between 0.5 g / L and 2 g / L; and / or in step S130, the third stirring temperature is between 20°C and 25°C; and / or the time for the first, second, and third stirring processes is between 0.5 h and 1 h; and / or the rotation speed for the first, second, and third stirring processes is between 70 rpm and 120 rpm; and / or the crosslinking agent includes at least one of glutaraldehyde, EDC, and NHS.

[0012] Compared with existing technologies, the technical effects achieved by this solution are as follows: By controlling the concentration range of laccase, cellulase, and pectinase, it is possible to effectively ensure that each enzyme achieves an appropriate catalytic effect. Concentrations within this range provide sufficient enzyme activity while avoiding waste of enzyme resources due to excessive concentrations. This balances the amount of enzyme used and its activity, reducing costs while ensuring efficiency. In step S110, the low-temperature stirring treatment effectively prevents thermal inactivation of laccase, ensuring its activity stability during preparation. Low-temperature treatment reduces the protein degradation rate, prolongs the effective activity time of the enzyme, which is beneficial for heat-sensitive enzymes and helps to ultimately improve the sustained activity of the composite enzyme preparation. In steps S120 and S130, stirring of cellulase and pectinase at room temperature enhances their molecular activity. This allows for more complete binding with the substrate, optimizing the enzymatic hydrolysis effect of the composite formulation and enhancing the synergistic effect between different enzyme layers. Selecting a stirring time of 0.5-1 hour and a rotation speed of 70-120 rpm ensures uniform dispersion of each enzyme while avoiding damage to the enzyme structure caused by over-stirring. It also prevents excessive mechanical shearing force from damaging the enzyme's active site, while ensuring sufficient binding of the enzyme with magnetic particles and cross-linking agents to form a stable composite structure. The cross-linking agent connects different enzymes to magnetic particles, effectively fixing the enzyme's position and preventing loss during use. Glutaraldehyde provides bifunctional groups, contributing to a strong cross-linking effect. EDC and NHS react under specific conditions to generate stable ester or amide bonds, immobilizing the enzyme on the surface of the magnetic particles, maintaining enzyme activity and enhancing the recyclability of the composite enzyme formulation.

[0013] In one technical solution of the present invention, in step S100, the pretreatment includes: water washing and oxidation treatment; and / or the temperature of the enzymatic hydrolysis treatment is between 45°C and 55°C; and / or the time of the enzymatic hydrolysis treatment is between 2h and 3h.

[0014] Compared with existing technologies, the technical effects achieved by this solution are as follows: Water washing removes dust, silt, and other impurities from the surface of the raw materials, reducing unnecessary pollution in subsequent processes and improving the purity of the slurry. It also reduces soluble substances in the raw materials, such as some soluble sugars or inorganic salts, preventing them from affecting enzyme activity or causing a decline in slurry quality in subsequent steps. Oxidation treatment removes some lignin, enhancing cellulose exposure, thereby improving enzymatic hydrolysis efficiency under low chemical additive conditions and offering environmental advantages. Within a temperature range of 45℃-55℃, the composite biological... The enzymatic activity of the bioenzyme preparation can reach a high level. This temperature ensures enzyme activity while avoiding high energy consumption or enzyme inactivation caused by excessively high temperatures, thus ensuring the efficiency of the enzymatic hydrolysis process and accelerating the decomposition of raw materials by the enzyme. Controlling the enzymatic hydrolysis time to 2-3 hours ensures that the compound bioenzyme fully decomposes the raw materials cellulose, hemicellulose, and pectin, while avoiding the waste of enzyme resources or possible fiber degradation caused by prolonged enzymatic hydrolysis. This partially softens and loosens the fiber structure, making subsequent mechanical pulping steps easier, further reducing energy consumption and improving pulping quality.

[0015] In one embodiment of the present invention, in step S200, the mass concentration of the slurry is adjusted to 12%-16%; and / or the pH value of the slurry is 5.5-6.5.

[0016] Compared with existing technologies, the technical effects achieved by this solution are as follows: At a mass concentration of 12%-16%, the pulp has a suitable fiber distribution density, which can effectively separate fiber bundles during mechanical pulping, helping to obtain a uniform pulp and improve the uniformity and quality of the final pulp. The moderate concentration also ensures appropriate friction and collision between fibers, enabling rapid separation in mechanical pulping equipment, reducing the time and energy consumption of mechanical pulping. Excessive concentration increases equipment load and wear, while excessively low concentration leads to low pulping efficiency. Therefore, this concentration balances equipment load and pulping efficiency, extending equipment lifespan. A pH value between 5.5 and 6.5 is the optimal activity range for the compound biological enzyme preparation. This pH condition ensures the stability and high activity of the enzyme in decomposing cellulose and hemicellulose, further improving pulping efficiency. Simultaneously, the fiber structure has high stability and will not be damaged by excessively low or high pH values, which helps maintain pulp strength and fiber length, improving the physical properties of the final pulp product.

[0017] In one technical solution of the present invention, in step S300, the bleaching treatment includes adding hydrogen peroxide to the slurry and reacting it for 3-5 hours at a temperature range of 45℃-55℃.

[0018] Compared with existing technologies, the technical effects achieved by this solution are as follows: At temperatures between 45℃ and 55℃, hydrogen peroxide has a stronger oxidizing ability, which can more effectively decompose impurities and pigment molecules in cellulose, thereby improving the bleaching effect and increasing the whiteness of the pulp. Bleaching at this temperature avoids fiber degradation or strength loss that may occur at high temperatures, ensuring the physical properties of the pulp and thus guaranteeing the toughness and strength of the finished pulp. Compared with higher temperature bleaching processes, this temperature range is more energy-efficient, meeting the goal of low energy consumption and contributing to overall energy conservation; reaction time... Blending for 3-5 hours allows hydrogen peroxide to fully oxidize and decompose impurities and pigment molecules in the pulp under mild conditions, resulting in higher bleaching uniformity and stability. This avoids excessive oxidation of fibers by hydrogen peroxide, protecting the fiber structure, maintaining the strength and quality of the pulp, and reducing hydrogen peroxide consumption. It also effectively oxidizes residual lignin and pigment molecules in the pulp, thereby improving pulp brightness and reducing the need for subsequent adjustments to the bleaching degree. Furthermore, hydrogen peroxide is an environmentally friendly bleaching agent that ultimately decomposes into water and oxygen during the bleaching process, without producing harmful byproducts, making it environmentally friendly.

[0019] In one embodiment of the present invention, in step S100, the softener includes at least one of polyvinyl alcohol, CTAC, and starch.

[0020] Compared with existing technologies, the technical effects achieved by this solution are as follows: Polyvinyl alcohol can form a soft protective film on the fiber surface, reducing friction between fibers, making the fibers softer and facilitating subsequent mechanical separation and pulping. It also possesses good film-forming and adhesive properties, improving the bonding strength between fibers, maintaining the strength and toughness of the pulp, thereby improving the physical properties of the finished paper. Simultaneously, polyvinyl alcohol can effectively disperse composite bio-enzymes, promoting their uniform distribution on the fiber surface and improving the uniformity and efficiency of enzymatic hydrolysis. CTAC, a cationic surfactant, can neutralize the negative charge on the fiber surface, reducing electrostatic repulsion between fibers, enhancing fiber flexibility, and facilitating better enzyme contact and action on the fibers. Furthermore, CTAC... It has a certain antibacterial effect, which can reduce the growth of microorganisms during pulping, prevent pulp contamination, ensure the purity and quality of pulp, improve pulp stability, prevent fiber agglomeration during enzymatic hydrolysis, promote uniform fiber dispersion, and enhance the enzymatic hydrolysis effect. Starch forms a hydrated film in the pulp, which helps to reduce the friction between fibers, improve fiber lubrication, and make fibers easier to disperse, which is beneficial to the subsequent mechanical pulping process. At the same time, the addition of starch can appropriately increase the viscosity of the pulp, thereby enhancing the stability of the pulp, avoiding fiber sedimentation or agglomeration, ensuring the uniformity of pulping, and because starch has a certain binding property, it can improve the mutual binding force between fibers, improve the strength and toughness of the final pulp, and help to obtain high-quality finished pulp.

[0021] In one embodiment of the present invention, the mass percentage of each component in the compound bio-enzyme preparation is as follows: laccase: 0.5%-5%, cellulase: 1%-5%, pectinase: 0.5%-2%.

[0022] Compared with existing technologies, the technical effects achieved by this solution are as follows: Laccase can oxidize and decompose lignin in fibers, reducing lignin residue in the fibers, improving the whiteness and purity of the pulp, making the remaining lignin in the fibers easier to bleach in subsequent processes, effectively reducing the amount of bleaching agent used, improving bleaching efficiency and reducing chemical residue. Furthermore, at this ratio, lignin is gently decomposed by laccase, reducing damage to fiber strength and thus maintaining the physical properties of the pulp. Cellulase can decompose microfibrils in the cellulose structure, reducing the compactness of the internal molecular structure of the fiber, making the fibers easier to separate during pulping, which is beneficial for pulp homogenization, making the fibers softer, and facilitating subsequent processing. Mechanical fiber separation and grinding processes reduce energy consumption and improve pulp uniformity. Furthermore, cellulase at this ratio increases fiber porosity and water absorption, contributing to the absorbency and flexibility of the finished pulp, meeting the requirements of high-quality paper. Pectinase decomposes pectin substances in plant cell walls, effectively removing pectin impurities from the pulp, improving pulp purity and brightness. Decomposing pectin reduces fiber adhesion, facilitating fiber dispersion and uniform distribution during pulping, preventing fiber agglomeration. In addition, pectinase at this ratio improves pulp fluidity and stability, making the pulp more uniform and stable throughout the pulping and bleaching process.

[0023] In one embodiment of the present invention, the mass percentages of each component in the compound bio-enzyme preparation are as follows: laccase: 1%, cellulase: 2%, and pectinase: 0.5%.

[0024] Compared with existing technologies, the technical effects achieved by this technical solution are as follows: through the formulation design of the compound bio-enzyme preparation, the efficient decomposition of lignin, cellulose, hemicellulose and pectin can be achieved during the pulping process, optimizing the enzymatic hydrolysis effect. Moreover, the compound bio-enzyme preparation at this component ratio can maximize the whiteness, purity and uniformity of the pulp, while reducing energy consumption and the use of chemical reagents, achieving an environmentally friendly and efficient pulping process, and ultimately obtaining high-quality pulp.

[0025] By adopting the technical solution of the present invention, the following technical effects can be achieved:

[0026] (1) The preparation method of this application optimizes the traditional pulping process by applying biological enzymes, improves production efficiency, shortens the production cycle, and reduces the operating costs of labor and equipment. Using biological enzymes to replace traditional chemical treatment not only reduces the use of chemical substances, but also reduces the emission of wastewater and waste gas, which is in line with the concept of green production.

[0027] (2) By layering and immobilizing the complex bio-enzymes, different raw material components can be decomposed in the required order. Laccase decomposes lignin to expose cellulose, then cellulase further acts on cellulose, and pectinase treats pectin components. The synergistic effect of the three effectively improves the raw material decomposition efficiency, ensuring that each enzyme plays its maximum role in its specific decomposition task and improving the overall enzymatic hydrolysis efficiency. At the same time, it reduces the direct contact between enzymes, avoids possible mutual inhibition or incompatibility, ensures the activity stability of each enzyme, and effectively reduces the enzyme activity loss that may be caused by interaction.

[0028] (3) The enzymes in each layer are fixed by magnetic particles, which reduces enzyme loss and provides physical support for each layer of enzymes, making it less likely for the enzymes to leave the composite system during the process, thus improving their stability and durability. In addition, the composite biological enzymes after layer fixation are magnetic, and the enzyme preparation can be quickly recovered from the slurry by an external magnetic field after the pulping is completed, thereby reducing enzyme consumption during the pulping process and enabling the enzyme preparation to be recycled multiple times, thereby reducing the cost of layer fixation technology. Detailed Implementation

[0029] To make the above-mentioned objectives, features, and advantages of the present invention more apparent and understandable, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Papermaking production consists of two basic processes: pulping and papermaking. Papermaking involves combining pulp fibers suspended in water through various processes to form paper sheets that meet various requirements. Biopulping is one of the technological directions for cleaning agent pulp. Biopulping produces pulp fibers that are long, have a high yield, and are highly durable. Moreover, the cost per ton of pulp is significantly lower than that of chemical and mechanical pulp. However, due to the high requirements for the cultivation and selection of biological strains and the conditions of the pulping process, there are many problems such as large production fluctuations, uneven material processing, excessively long processing times, and low production efficiency. Currently, biopulping is still difficult to achieve industrial-scale production.

[0031] Traditional mechanical pulping methods typically require a large amount of energy, leading to high production costs. Energy consumption not only affects economic efficiency but also exacerbates the environmental burden; at the same time, the pulping process is slow, and the efficiency of enzymatic hydrolysis and mechanical processing is low, affecting overall production efficiency.

[0032] Therefore, this invention provides a low-energy pulping method assisted by a composite bio-enzyme, aiming to solve the problems of high energy consumption and low efficiency in traditional pulping processes. By using composite bio-enzymes such as laccase, cellulase, and pectinase, and by using ultrasound during enzymatic hydrolysis, the activity and hydrolysis efficiency of the enzymes can be improved, thereby enhancing the hydrolysis efficiency of the raw materials and reducing energy consumption. At the same time, different enzymes are processed and cross-linked in steps to ensure that each enzyme reacts under optimal conditions, thereby increasing reaction efficiency.

[0033] The preparation methods of compound biological enzyme preparations include:

[0034] S110: Laccase is dispersed in phosphate buffer solution, then magnetic particles are added, and a first stirring treatment is performed. A cross-linking agent is added, and after the reaction is completed, the mixture is washed with phosphate buffer solution to obtain the first solvent. Preferably, the concentration of laccase is between 6.0 g / L and 7.0 g / L. The first stirring treatment temperature is 3℃-6℃. Low-temperature stirring treatment can effectively prevent the thermal inactivation of laccase and ensure its activity stability during the preparation process. Low-temperature treatment reduces the degradation rate of proteins and prolongs the effective activity time of enzymes, which is beneficial to heat-sensitive enzymes and helps to ultimately improve the long-lasting activity of the compound enzyme preparation.

[0035] S120: Cellulase is dispersed in phosphate buffer, a first solvent is added, a second stirring treatment is performed, a cross-linking agent is added, and the mixture is washed with phosphate buffer after the reaction is completed to obtain a second solvent; preferably, the concentration of cellulose is between 1.0 g / L and 5.0 g / L, and the temperature of the second stirring treatment is 20℃-25℃;

[0036] S130: Pectinase is dispersed in phosphate buffer, a second solvent is added, a third stirring treatment is performed, a cross-linking agent is added, and the mixture is washed with phosphate buffer after the reaction is completed to obtain the third solvent; preferably, the concentration of pectin is between 0.5 g / L and 2 g / L, and the third stirring treatment temperature is 20℃-25℃. At this temperature, the molecular activity of cellulase and pectinase is enhanced, which can bind more fully to the substrate, optimize the enzymatic hydrolysis effect of the compound preparation, and improve the synergistic effect between different enzyme levels;

[0037] Furthermore, the first, second, and third stirring treatments are conducted for 0.5-1 hour at a speed of 70-120 rpm. The cross-linking agent includes at least one of glutaraldehyde, EDC, and NHS. Choosing a stirring time of 0.5-1 hour and a speed of 70-120 rpm ensures uniform dispersion of the enzymes while avoiding damage to the enzyme structure caused by over-stirring. It also prevents excessive mechanical shearing from damaging the enzyme's active site, while ensuring sufficient binding between the enzyme, magnetic particles, and cross-linking agent to form a stable composite structure. The cross-linking agent connects different enzymes to the magnetic particles, effectively fixing the enzyme's position and preventing loss during use. Glutaraldehyde provides bifunctional groups, contributing to a strong cross-linking effect. EDC and NHS react under specific conditions to generate stable ester or amide bonds, fixing the enzyme to the surface of the magnetic particles, thus maintaining enzyme activity and enhancing the recyclability of the composite enzyme preparation.

[0038] S140: The third solvent is washed clean with phosphate buffer to obtain the composite biological enzyme preparation.

[0039] S100: The raw materials are pretreated, then a compound biological enzyme preparation and a softener are added, and the mixture is enzymatically hydrolyzed under ultrasound to obtain a mixture;

[0040] Preferably, the pretreatment includes water washing and oxidation treatment. Water washing can remove dust, mud and other impurities from the surface of the raw materials, reduce unnecessary pollution in subsequent processes, improve the purity of the slurry, and reduce soluble substances in the raw materials, such as some soluble sugars or inorganic salts, to avoid affecting enzyme activity or causing a decline in slurry quality in subsequent steps. Oxidation treatment can remove some lignin and enhance the exposure of cellulose, thereby improving the enzymatic hydrolysis effect under low chemical additive conditions and having environmental advantages.

[0041] The enzymatic hydrolysis temperature is between 45℃ and 55℃. The enzymatic hydrolysis activity of the compound biological enzyme preparation can reach a high level. This temperature can ensure the activity of the enzyme while avoiding the high energy consumption or enzyme inactivation caused by excessively high temperature, thereby ensuring the efficiency of the enzymatic hydrolysis process and accelerating the decomposition of raw materials by the enzyme.

[0042] The enzymatic hydrolysis time is 2-3 hours, which can ensure that the compound bio-enzyme fully decomposes the raw material cellulose, hemicellulose and pectin, while avoiding the waste of enzyme resources or possible fiber degradation caused by long-term enzymatic hydrolysis. This softens and loosens the fiber structure, making the subsequent mechanical pulping steps easier, further reducing energy consumption and improving pulping quality.

[0043] S200: The mixture is mechanically pulped and then separated into fibers using a grinding machine to form a slurry;

[0044] Preferably, the mass concentration of the pulp is adjusted to 12%-16%. The pulp has a suitable fiber distribution density, which can effectively separate fiber bundles during mechanical pulping, helping to obtain a uniform pulp and improve the uniformity and quality of the final pulp. The appropriate concentration also ensures that the friction and collision between fibers are moderate, enabling rapid separation in mechanical pulping equipment and reducing mechanical pulping time and energy consumption. Too high a concentration will increase the equipment load and wear, while too low a concentration will lead to low pulping efficiency. Therefore, this concentration balances the equipment load and pulping efficiency, and extends the service life of the equipment.

[0045] Furthermore, the optimal activity range for the compound bio-enzyme preparation is between pH 5.5 and 6.5. This pH condition ensures the stability and high activity of the enzyme when decomposing cellulose and hemicellulose, further improving pulping efficiency. At the same time, the fiber structure is highly stable and will not be damaged due to excessively low or high pH values, which helps maintain the strength and fiber length of the pulp and improves the physical properties of the final pulp product.

[0046] S300: Bleaching and cleaning treatment of the pulp to complete the pulping process; the compound biological enzyme preparation includes laccase, cellulase and pectinase, and magnetic particles.

[0047] Preferably, the bleaching treatment involves a temperature range of 45℃-55℃, where hydrogen peroxide has a strong oxidizing ability and can more effectively decompose impurities and pigment molecules in cellulose, thereby improving the bleaching effect and increasing the whiteness of the pulp. Bleaching at this temperature avoids fiber degradation or strength loss that may occur at high temperatures, ensuring the physical properties of the pulp and thus guaranteeing the toughness and strength of the finished pulp. Compared to bleaching processes at higher temperatures, this temperature range is more energy-efficient, meeting the goal of low energy consumption and contributing to overall energy conservation; the reaction time is 3-5 hours. Hydrogen peroxide can fully oxidize and decompose impurities and pigment molecules in pulp under mild conditions, resulting in high bleaching uniformity and stability. It can avoid excessive oxidation of fibers by hydrogen peroxide, protect the fiber structure, maintain the strength and quality of pulp, and reduce the consumption of hydrogen peroxide. At the same time, it can effectively oxidize lignin and pigment molecules remaining in the pulp, thereby improving the brightness of the pulp and reducing the need for subsequent adjustments to the bleaching degree. In addition, hydrogen peroxide is an environmentally friendly bleaching agent. During the bleaching process, it eventually decomposes into water and oxygen without producing harmful byproducts, making it environmentally friendly.

[0048] Example 1:

[0049] This embodiment provides a low-energy pulping method assisted by a composite biological enzyme, the steps of which are as follows:

[0050] S100: The raw material is soaked in deionized water, and the water is circulated by mechanical stirring or pumping for 0.45 hours of water washing. Then, oxygen is added to the washed raw material for oxidation treatment. Then, a compound biological enzyme preparation and a softener are added, and enzymatic hydrolysis is carried out under ultrasonic treatment at 50°C for 2.5 hours to obtain a mixture. The softener includes polyvinyl alcohol, CTAC, and starch. The compound biological enzyme preparation includes laccase: 1%, cellulase: 2%, and pectinase: 0.5%.

[0051] S200: The mixture is mechanically pulped and separated into fibers by a grinding machine to form a slurry with a mass concentration of 14% and a pH value of 6.

[0052] S300: Add hydrogen peroxide to the slurry, bleach it at 50°C, and then wash it three times to complete the pulping process.

[0053] The preparation method of the compound biological enzyme preparation is as follows:

[0054] S110: 6.5 g / L laccase was dispersed in phosphate buffer solution, and then iron oxide magnetic particles were added. The mixture was stirred for 0.8 h at 5 °C and 100 rpm. Glutaraldehyde was added. After the reaction was completed, the mixture was washed with phosphate buffer solution to obtain the first solvent.

[0055] S120: Disperse 3.0 g / L cellulase in phosphate buffer, add the first solvent, and perform a second stirring treatment at 22℃ and 100 rpm for 0.8 h. Add glutaraldehyde, and wash with phosphate buffer after the reaction is complete to obtain the second solvent.

[0056] S130: 1.0 g / L pectinase was dispersed in phosphate buffer, a second solvent was added, and the mixture was stirred for 0.8 h at 22 °C and 100 rpm. Glutaraldehyde was added, and the mixture was washed with phosphate buffer after the reaction was completed to obtain a third solvent.

[0057] S140: The third solvent is washed clean with phosphate buffer to obtain the composite biological enzyme preparation.

[0058] Example 2:

[0059] This embodiment provides a low-energy pulping method assisted by a composite biological enzyme, the steps of which are as follows:

[0060] S100: The raw material is soaked in deionized water, and the water is circulated by mechanical stirring or pumping for 0.3 hours of water washing. Then ozone is added to the washed raw material for oxidation treatment. Then, a compound biological enzyme preparation and a softener are added, and the mixture is enzymatically hydrolyzed under ultrasound at 45°C for 2 hours to obtain a mixture. The softener includes polyvinyl alcohol, CTAC, and starch. The compound biological enzyme preparation includes laccase: 0.5%, cellulase: 1%, and pectinase: 1%.

[0061] S200: The mixture is mechanically pulped and then separated into fibers using a grinding machine to form a slurry with a mass concentration of 12% and a pH value of 5.5.

[0062] S300: Add hydrogen peroxide to the pulp, bleach it at 45°C, and then wash it 5 times to complete the pulping process;

[0063] The preparation method of the compound biological enzyme preparation is as follows:

[0064] S110: 6.0 g / L laccase was dispersed in phosphate buffer solution, and then iron oxide magnetic particles were added. The mixture was stirred for 0.5 h at 3 °C and 700 rpm. EDC was added. After the reaction was completed, the mixture was washed with phosphate buffer solution to obtain the first solvent.

[0065] S120: Disperse 1.0 g / L cellulase in phosphate buffer, add the first solvent, and perform a second stirring treatment at 20℃ and 70 rpm for 0.5 h. Add EDC, and wash with phosphate buffer after the reaction is complete to obtain the second solvent.

[0066] S130: Disperse 0.5 g / L pectinase in phosphate buffer, add the second solvent, and perform a second stirring treatment at 20℃ and 70 rpm for 0.5 h. Add EDC, and wash with phosphate buffer after the reaction is complete to obtain the third solvent.

[0067] S140: The third solvent is washed clean with phosphate buffer to obtain the composite biological enzyme preparation.

[0068] Example 3:

[0069] This embodiment provides a low-energy pulping method assisted by a composite biological enzyme, the steps of which are as follows:

[0070] S100: The raw material is soaked in deionized water, and the water is circulated by mechanical stirring or pumping for 1 hour of water washing. Then, hydrogen peroxide is added to the washed raw material for oxidation treatment. Then, a compound biological enzyme preparation and a softener are added, and the mixture is enzymatically hydrolyzed at 55°C under ultrasonic conditions for 3 hours to obtain a mixture. The softener includes polyvinyl alcohol, CTAC, and starch. The compound biological enzyme preparation includes laccase: 5%, cellulase: 5%, and pectinase: 2%.

[0071] S200: The mixture is mechanically pulped and then separated into fibers using a grinding machine to form a slurry with a mass concentration of 16% and a pH value of 6.5.

[0072] S300: Add hydrogen peroxide to the pulp, bleach it at 55°C, and then wash it three times to complete the pulping process.

[0073] The preparation method of the compound biological enzyme preparation is as follows:

[0074] S110: 7.0 g / L laccase was dispersed in phosphate buffer solution, and then iron oxide magnetic particles were added. The mixture was stirred for 1 h at 6 °C and 120 rpm. NHS was added. After the reaction was completed, the mixture was washed with phosphate buffer solution to obtain the first solvent.

[0075] S120: Disperse 5.0 g / L cellulase in phosphate buffer, add the first solvent, and perform a second stirring treatment at 25℃ and 120 rpm for 1 h. Add NHS, and wash with phosphate buffer after the reaction is complete to obtain the second solvent.

[0076] S130: 2.0 g / L pectinase was dispersed in phosphate buffer, a second solvent was added, and the mixture was stirred for 1 hour at 25°C and 120 rpm. NHS was added, and the mixture was washed with phosphate buffer after the reaction was completed to obtain a third solvent.

[0077] S140: The third solvent is washed clean with phosphate buffer to obtain the composite biological enzyme preparation.

[0078] Comparative Example 1:

[0079] This comparative example provides a bio-enzyme-assisted, low-energy pulping method, the steps of which are as follows:

[0080] S100: The raw material is soaked in deionized water, and the water is made to flow by mechanical stirring or pumping for 1 hour of water washing. Then oxygen is added to the washed raw material for oxidation treatment. Then laccase and softener are added, and enzymatic hydrolysis is carried out under ultrasonic treatment at 50°C for 2.5 hours to obtain a mixture. The softener includes polyvinyl alcohol, CTAC and starch.

[0081] S200: The mixture is mechanically pulped and then separated into fibers using a grinding machine to form a slurry with a mass concentration of 16% and a pH value of 6.5.

[0082] S300: Add hydrogen peroxide to the slurry and bleach it at 55°C, then wash it three times to complete the pulping process.

[0083] Comparative Example 2:

[0084] This comparative example provides a low-energy pulping method assisted by a composite biological enzyme, the steps of which are as follows:

[0085] S100: The raw material is soaked in deionized water, and the water is circulated by mechanical stirring or pumping for 1 hour of water washing. Then, oxygen is added to the washed raw material for oxidation treatment. Next, a mixture containing compound biological enzymes and softening agents is added, and enzymatic hydrolysis is carried out under ultrasonic treatment at 50°C for 2.5 hours to obtain a mixture. The softening agents include polyvinyl alcohol, CTAC, and starch. The compound biological enzymes include laccase: 1%, cellulase: 2%, pectinase: 0.5%, and the balance is mixed with water.

[0086] S200: The mixture is mechanically pulped and then separated into fibers using a grinding machine to form a slurry with a mass concentration of 16% and a pH value of 6.5.

[0087] S300: Add hydrogen peroxide to the slurry and bleach it at 55°C, then wash it three times to complete the pulping process.

[0088] Performance testing:

[0089] Performance tests were conducted on Examples 1 to 3 and the comparative example, and all test methods followed national standards. The quantitative determination of the hand-coated sheet was 70 g / m³. 2 The actual basis weight of the paper sheets was determined and weighed according to the national standard (GB / T451.2-2002). Whiteness was measured according to the national standard GB / T7974-2013; the pulp tear index was measured according to the national standard GB / T455-2002; and the tensile index was measured according to the national standard GB / T453-2002. Pulping power consumption and pulp yield were also recorded, as shown in Table 1.

[0090] Table 1

[0091] Example 1 855 95.5 49.26 Example 2 946 94.2 47.65 Example 3 904 94.8 48.55 Comparative Example 1 1256 86.8 45.65 Comparative Example 2 1045 90.56 46.65

[0092] As shown in the table above, the power consumption and slurry yield in the preparation process of the slurry in the examples are significantly different from those in the comparative examples, while the whiteness does not change significantly. This indicates that the synergistic effect of multiple enzymes in the compound biological enzyme preparation can significantly reduce power consumption.

[0093] The mechanical properties of the paper products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured, and the results are shown in Table 2:

[0094] Table 2

[0095]

[0096]

[0097] As shown in the table above, the tensile index and ring crush index of the paper prepared in the examples are much higher than those of the paper in the comparative example. The paper prepared in the examples has a significantly higher tensile index, indicating that the pulping method makes the fibers more tightly bonded and the structure more robust. This is due to the synergistic effect of cellulase and pectinase in the compound enzyme preparation, which can effectively degrade impurities between fibers and promote the enhancement of fiber bonding. The higher ring crush index of the examples means that the paper prepared by this method is superior in terms of pressure resistance and durability. This is because the layered fixation technology makes the various enzymes (laccase, cellulase, pectinase) more evenly distributed on the fiber surface and has a longer-lasting effect, thereby improving the fiber adhesion and the structural strength of the paper. Through layered fixation, different enzymes in the compound biological enzyme preparation can act on the fibers sequentially under suitable conditions, avoiding mutual interference between enzymes and improving the catalytic efficiency of enzymes. This makes the enzymatic hydrolysis and pulping in the examples more efficient and effective, so the efficiency of Examples 1 to 3 far exceeds that of Comparative Example 2.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-energy grinding method assisted by a composite bio-enzyme, characterized in that, The method includes: S100: The raw materials are pretreated, then a compound biological enzyme preparation and a softener are added, and the mixture is enzymatically hydrolyzed under ultrasound to obtain a mixture; S200: The mixture is mechanically pulped and then separated into fibers using a grinding device to form a slurry; S300: The slurry is bleached and cleaned to complete the pulping process; The composite bio-enzyme preparation includes laccase, cellulase, pectinase, and magnetic particles; the mass percentages of each component in the composite bio-enzyme preparation are as follows: laccase: 0.5%-5%, cellulase: 1%-5%, pectinase: 0.5%-2%; The preparation method of the compound bio-enzyme preparation includes: S110: The laccase is dispersed in a phosphate buffer solution, then magnetic particles are added, and the mixture is stirred for the first time. A cross-linking agent is added, and after the reaction is completed, the mixture is washed with a phosphate buffer solution to obtain the first solvent. S120: The cellulase is dispersed in phosphate buffer, the first solvent is added, a second stirring treatment is performed, the cross-linking agent is added, and after the reaction is completed, the mixture is washed with phosphate buffer to obtain the second solvent; S130: The pectinase is dispersed in phosphate buffer, the second solvent is added, and a third stirring treatment is performed. The cross-linking agent is added, and after the reaction is completed, the mixture is washed with phosphate buffer to obtain the third solvent. S140: The third solvent is washed clean with phosphate buffer to obtain the composite biological enzyme preparation.

2. The method according to claim 1, characterized in that, In step S110, the concentration of the laccase is between 6.0 g / L and 7.0 g / L; and / or In step S110, the temperature of the first stirring process is between 3°C and 6°C; and / or In step S120, the concentration of the cellulose is between 1.0 g / L and 5.0 g / L; and / or In step S120, the temperature of the second stirring process is between 20°C and 25°C; and / or In step S130, the concentration of the pectinase is between 0.5 g / L and 2.0 g / L; and / or In step S130, the temperature of the third stirring process is between 20°C and 25°C; and / or The duration of the first, second, and third stirring treatments is between 0.5 h and 1 h; and / or The stirring speeds for the first, second, and third stirring processes are between 70 rpm and 120 rpm; and / or The crosslinking agent includes at least one of glutaraldehyde, EDC, and NHS.

3. The method according to claim 1, characterized in that, In step S100, The pretreatment includes: water washing and oxidation treatment; and / or The enzymatic hydrolysis treatment is performed at a temperature between 45°C and 55°C; and / or The enzymatic hydrolysis treatment time is between 2h and 3h.

4. The method according to claim 1, characterized in that, In step S200, The mass concentration of the slurry is adjusted to between 12% and 16%; and / or The pH value of the slurry is between 5.5 and 6.

5.

5. The method according to claim 1, characterized in that, In step S300, the bleaching treatment includes adding hydrogen peroxide to the slurry and reacting it for 3-5 hours at a temperature range of 45℃-55℃.

6. The method according to claim 1, characterized in that, In step S100, the softener includes at least one of polyvinyl alcohol, CTAC, and starch.

7. The method according to claim 1, characterized in that, In the compound bio-enzyme preparation, the mass percentage of each component is as follows: laccase: 1%, cellulase: 2%, pectinase: 0.5%.

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