Enzymolysis method of lignocellulose
By using choline chloride, sodium sulfite and additives to perform hydrothermal reactions in the pretreatment of lignocellulose, the structure of lignocellulose is broken, and the pretreatment liquid is used as an enzymatic aid to solve the problems of low enzymatic elusion and high production cost of lignocellulose, and efficient enzymatic elusion and comprehensive utilization are achieved.
Patent Information
- Application Number
- CN202510093643.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-04-25
AI Technical Summary
In the prior art, the enzymatic efficiency of lignocellulose is low, and the pretreatment method has problems such as high energy consumption, pollution of the environment and the production of fermentation inhibitors. The cellulase activity and large amount of use lead to high production costs.
The lignocellulose is pretreated by choline chloride, sodium sulfite and additives (such as acrylamide and rare earth compounds). The lignocellulose structure is broken through hydrothermal reaction, the pretreatment temperature is reduced, and energy consumption is reduced. The pretreatment liquid is used as an enzymatic aid to improve the activity and stability of the cellulase.
It significantly improves the enzymatic decomposition rate of lignocellulose, reduces production costs, reduces energy consumption and pollution, and realizes efficient enzymatic decomposition and comprehensive utilization of lignocellulose.
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Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of enzymatic hydrolysis of lignocellulose, and in particular to a method for enzymatic hydrolysis of lignocellulose. Background Art
[0002] The use of lignocellulosic raw materials as renewable energy is the most promising alternative to the current reliance on fossil resources. In recent years, the use of lignocellulosic raw materials to produce bio-based materials, chemicals and bioenergy has become a research hotspot. After pretreatment and enzymatic saccharification, lignocellulosic raw materials can be used to obtain fermentable sugar hydrolysate, which can then be used to produce industrial products such as fuel ethanol and lactic acid. The complex structure of lignocellulosic cellulose makes it difficult to depolymerize and the low efficiency of cellulose saccharification and enzymatic hydrolysis limits the industrial application of lignocellulosic raw materials.
[0003] At present, the structure of lignocellulose is mainly broken by pretreatment to fractionate each component to achieve full component utilization. However, the traditional alkali treatment has the problems of large waste liquid treatment volume and high environmental pressure in the later stage. The steam explosion pretreatment has the problem of incomplete lignin removal, and it is easy to produce substances such as furfural that inhibit microbial growth. The above pretreatment methods often cause the dissolved lignin to re-condense and deposit on the surface of the substrate after pretreatment to form lignin deposits. These lignin deposits have strong hydrophobicity and high phenolic hydroxyl content, and often cause ineffective adsorption of cellulase in the subsequent enzymatic hydrolysis process, resulting in unnecessary loss of cellulase, which is not conducive to the subsequent enzymatic hydrolysis of the substrate. Although lignin redeposition can be removed by secondary pretreatment, this undoubtedly increases the operation steps and increases the investment cost. Although increasing the amount of cellulase will obtain a higher enzymatic hydrolysis rate and a high concentration of fermentable sugar, it undoubtedly increases the production cost. The above-mentioned lignocellulose raw material hydrolysis sugar production still faces many technical bottlenecks, such as high energy consumption in pretreatment, environmental pollution and the production of fermentation inhibitors, as well as low specific activity of cellulase, large enzyme dosage, and so on. In this context, it is particularly important to study efficient pretreatment methods for lignocellulosic raw materials to improve the enzymatic hydrolysis of substrates. Summary of the invention
[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an enzymatic hydrolysis method for lignocellulose, which can improve the enzymatic hydrolysis rate of lignocellulose.
[0005] To achieve the above object, the technical solution adopted by the present disclosure is: a method for enzymatic hydrolysis of lignocellulose, comprising the following steps:
[0006] Pretreatment: Mix lignocellulose, additives, choline chloride, sodium sulfite and water evenly, perform hydrothermal reaction at a temperature of 160-180°C, separate the reaction products into solid and liquid, and obtain a solid matrix and a pretreatment liquid;
[0007] Enzymatic hydrolysis: the solid matrix, the pretreatment solution and the buffer solution are mixed evenly to obtain a first solution, cellulase is added to the first solution to perform enzymatic hydrolysis to obtain an enzymatic hydrolyzate;
[0008] The additive is at least one of acrylamide, hydroxyethyl acrylate and a rare earth compound.
[0009] In some embodiments, based on 100 parts by weight of lignocellulose, the following components are included in parts by weight: 0.5-10 parts of additives, 5-15 parts of choline chloride, 5-100 parts of sodium sulfite, and 400-800 parts of water.
[0010] In some embodiments, the rare earth compound is at least one of gallium trichloride, gallium oxide, and yttrium oxide.
[0011] In some embodiments, the hydrothermal reaction time is 2-4 hours.
[0012] In some embodiments, the ratio of the mass of the solid matrix to the total volume of the pretreatment solution and the buffer solution is 2 g:100 mL-10 g:100 mL.
[0013] In some embodiments, the volume of the pretreatment solution is 2-5% of the total volume of the pretreatment solution and the buffer solution.
[0014] In some embodiments, the enzymatic hydrolysis temperature is 40-60°C, the rotation speed is 100-200 rpm, and the time is 48-96 hours.
[0015] In some embodiments, the amount of the cellulase is 3-30 FPU / g based on the mass of lignocellulose.
[0016] In some embodiments, the pH of the buffer solution is 4.5-6.0, and the ionic strength is 25-100 mmol / L.
[0017] In some embodiments, the wood cellulose is at least one of filter paper cellulose, microcrystalline cellulose, pine, eucalyptus, poplar, corn cob, corn stover, wheat straw, bagasse and rice straw.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] (1) The present invention uses choline chloride, sodium sulfite and additives to pretreat lignocellulosic raw materials, thereby breaking the dense and complex structure of the lignocellulosic raw materials and modifying the lignocellulosic structure to make it easy for enzymatic hydrolysis. It can reduce the pretreatment temperature without reducing the sugar production of the pretreatment matrix, significantly reduce energy consumption, and improve the pretreatment effect.
[0020] (2) The present invention utilizes the pretreatment liquid of lignocellulose as an enzymatic hydrolysis aid, which can improve the enzyme activity and stability of saccharifying and hydrolyzing enzymes, reduce the enzyme dosage and increase the enzymatic hydrolysis saccharification yield of lignocellulose, thereby reducing the production cost of converting lignocellulose into fermentable sugars; the pretreatment liquid that inhibits the enzymatic hydrolysis of lignocellulose is turned into treasure, thereby realizing the comprehensive utilization of lignocellulose. DETAILED DESCRIPTION
[0021] In order to facilitate understanding of the present disclosure, the present disclosure will be described more fully below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present disclosure more thorough and comprehensive.
[0022] As used herein:
[0023] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
[0024] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.
[0025] When amount, concentration or other value or parameter is represented by range, preferred range or a series of upper preferred value and lower preferred value, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1-5", described range should be interpreted as including range "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.
[0026] In these examples, parts and percentages are by mass unless otherwise indicated.
[0027] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.
[0028] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).
[0029] The present invention provides a method for enzymatic hydrolysis of lignocellulose, comprising the following steps:
[0030] Pretreatment: Mix lignocellulose, additives, choline chloride, sodium sulfite and water evenly, perform hydrothermal reaction at a temperature of 160-180°C, separate the reaction products into solid and liquid, and obtain a solid matrix and a pretreatment liquid;
[0031] Enzymatic hydrolysis: the solid matrix, the pretreatment solution and the buffer solution are mixed evenly to obtain a first solution, cellulase is added to the first solution to perform enzymatic hydrolysis to obtain an enzymatic hydrolyzate;
[0032] The additive is at least one of acrylamide, hydroxyethyl acrylate and a rare earth compound.
[0033] The present invention uses choline chloride, sodium sulfite and additives to pretreat lignocellulose raw materials, break the dense and complex structure of lignocellulose raw materials, on the one hand reduce the fracture of lignin β-O-4 bonds, inhibit the generation of phenolic hydroxyl groups, and then reduce the side reactions of non-productive adsorption of cellulase involved in lignin, improve the utilization rate of cellulase, on the other hand, in the hydrolysis process, the propylene segment and / or rare earth element in the additive can be embedded in the lignin structure, inhibit lignin re-condensation, retain more β-O-4 bonds, can not reduce the sugar production of pretreatment matrix under the condition of lowering the pretreatment temperature, significantly reduce energy consumption, and improve the pretreatment effect. In the enzymatic hydrolysis process, the pretreatment liquid of lignocellulose is used as an enzymatic hydrolysis auxiliary agent, which can improve the enzyme activity and stability of saccharification and hydrolysis enzymes, reduce the enzyme dosage and improve the enzymatic hydrolysis saccharification yield of lignocellulose, and reduce the production cost of lignocellulose converted into fermentable sugars; the pretreatment liquid that inhibits the enzymatic hydrolysis of lignocellulose is turned into treasure, and the comprehensive utilization of lignocellulose is realized.
[0034] In order to improve the effect of pretreatment, lignocellulose needs to be crushed before hydrothermal reaction. The specific steps are as follows:
[0035] The lignocellulose raw material with a length of 2-3 cm is added into a pulverizer for pulverization, and the pulverized material is dried to obtain lignocellulose powder.
[0036] Specifically, the particle size of the wood cellulose powder is 50-200 meshes.
[0037] Specifically, the mass fraction of the total solid in the wood cellulose powder is 90-92%, and the testing method thereof is: the method in NREL / TP-510-42618 of the United States Renewable Energy Laboratory is used for determination.
[0038] Specifically, the mass fraction of volatile solids in the wood cellulose powder is 80-85%, and the testing method is: calcining in a muffle furnace at a temperature of 550°C to constant weight, using an electronic balance to measure the mass of the wood cellulose powder before and after calcination, the mass fraction of volatile solids in the wood cellulose powder = (mass before calcination - mass after calcination) / mass before calcination × 100%.
[0039] In order to improve the enzymatic hydrolysis effect of the solid matrix, the present disclosure adopts a washing and drying method to remove impurities from the solid product obtained by solid-liquid separation. The specific steps are as follows:
[0040] The solid product obtained by solid-liquid separation is washed with deionized water until it is neutral, and dried to obtain a solid matrix.
[0041] Specifically, the drying temperature is 50-110°C, for example, it can be but not limited to 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C.
[0042] In some embodiments, based on 100 parts by weight of lignocellulose, the following components are included in parts by weight: 0.5-10 parts of additives, 5-15 parts of choline chloride, 5-100 parts of sodium sulfite, and 400-800 parts of water.
[0043] For example, in different embodiments, the weight proportion of the additive may be, but is not limited to, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts, preferably 3-10 parts, and more preferably 5-10 parts.
[0044] For example, in different embodiments, the weight proportion of the choline chloride can be, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts.
[0045] For example, in different embodiments, the weight parts of the sodium sulfite can be but are not limited to 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 75 parts, 90 parts, 95 parts, and 100 parts.
[0046] For example, in different embodiments, the weight proportion of the water may be, but is not limited to, 400 parts, 450 parts, 500 parts, 550 parts, 600 parts, 650 parts, 700 parts, 750 parts, or 800 parts.
[0047] During the pretreatment process, the addition amount of each component will affect the enzymatic saccharification yield of lignocellulose. For example, if the weight proportion of additives, choline chloride and sodium sulfite is too high, the activity of cellulase components will be weakened, thereby reducing the enzymatic saccharification rate. If the weight proportion of additives, choline chloride and sodium sulfite is too low, the lignin removal effect will be poor, resulting in insufficient enzymatic hydrolysis of holocellulose and a low yield of mixed sugars.
[0048] In some embodiments, the rare earth compound is at least one of gallium trichloride, gallium oxide, and yttrium oxide.
[0049] The rare earth compounds can effectively improve the enzymatic hydrolysis rate of lignocellulose.
[0050] In some embodiments, the hydrothermal reaction time is 2-4 hours, for example, but not limited to 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours.
[0051] In some embodiments, the ratio of the mass of the solid matrix to the total volume of the pretreatment solution and the buffer solution is 2g:100mL-10g:100mL, for example, but not limited to 2g:100mL, 3g:100mL, 4g:100mL, 5g:100mL, 6g:100mL, 7g:100mL, 8g:100mL, 9g:100mL, and 10g:100mL.
[0052] In the present disclosure, the ratio of the mass of the solid matrix to the total volume of the pretreatment liquid and the buffer solution is too high, so that the reaction system is in a solid phase state, and the hydrothermal pretreatment has a poor effect on the structural depolymerization of cellulose, resulting in a low enzymatic saccharification yield; the ratio of the mass of the solid matrix to the total volume of the pretreatment liquid and the buffer solution is too high, the cellulose depolymerization effect is good, and the enzymatic saccharification yield is high, but there are problems such as low concentration of reaction materials and weak raw material processing capacity, resulting in high cost.
[0053] In some embodiments, the volume of the pretreatment solution is 2-5% of the total volume of the pretreatment solution and the buffer solution, for example, but not limited to 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.
[0054] In the present disclosure, the percentage of the volume of the pretreatment liquid to the total volume of the pretreatment liquid and the buffer solution is too high, and the pretreatment liquid contains additives, choline chloride, rare earth elements and other components that will inhibit the activity of cellulase, thereby reducing the enzymatic saccharification performance. The percentage of the volume of the pretreatment liquid to the total volume of the pretreatment liquid and the buffer solution is too low, and the pretreatment liquid contains additives, choline chloride, rare earth elements and other components that cannot promote the activity of the cellulase preparation, and thus the enzymatic hydrolysis performance of holocellulose is not significantly improved.
[0055] In some embodiments, the enzymatic hydrolysis temperature is 40-60°C, the rotation speed is 100-200 rpm, and the time is 48-96 hours.
[0056] For example, in different embodiments, the temperature of the enzymatic hydrolysis may be, but is not limited to, 40°C, 42°C, 45°C, 47°C, 50°C, 53°C, 55°C, 58°C, or 60°C.
[0057] For example, in different embodiments, the rotation speed of the enzymatic hydrolysis can be, but is not limited to, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, or 200 rpm.
[0058] For example, in different embodiments, the enzymatic hydrolysis time can be but is not limited to 48 h, 52 h, 56 h, 60 h, 64 h, 68 h, 72 h, 76 h, 80 h, 84 h, 88 h, 92 h, and 96 h.
[0059] In some embodiments, the amount of the cellulase is 3-30 FPU / g based on the mass of cellulose, for example, it can be but not limited to 3FPU / g, 6FPU / g, 9FPU / g, 12FPU / g, 15FPU / g, 18FPU / g, 21FPU / g, 24FPU / g, 27FPU / g, 30FPU / g.
[0060] In some embodiments, the pH of the buffer solution is 4.5-6.0, for example, it can be but not limited to 4.5, 4.8, 5.1, 5.4, 5.7, 6.0; the ionic strength is 25-100mmol / L, for example, it can be but not limited to 25mmol / L, 30mmol / L, 40mmol / L, 50mmol / L, 60mmol / L, 70mmol / L, 80mmol / L, 90mmol / L, 100mmol / L.
[0061] Specifically, the buffer solution is one of citric acid-sodium citrate, acetic acid-sodium acetate, ammonia water-ammonium chloride, sodium dihydrogen phosphate-disodium hydrogen phosphate.
[0062] In some embodiments, the wood cellulose is at least one of filter paper cellulose, microcrystalline cellulose, pine, eucalyptus, poplar, corn cob, corn stover, wheat straw, bagasse and rice straw.
[0063] In order to further illustrate the present invention, the enzymatic hydrolysis method of lignocellulose provided by the present invention is described in detail below in conjunction with the examples, but they should not be construed as limiting the scope of protection of the present invention.
[0064] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:
[0065] Lignocellulose powder: Cut corn stalks into small pieces of 2-3 cm, grind them in a grinder, pass them through a 150-mesh sieve, and then dry them in an oven at 70° C. to constant weight to obtain lignin cellulose powder for later use; wherein the mass fraction of total solids in the lignin cellulose powder is 90.04%, and the mass fraction of volatile solids in the lignin cellulose powder is 82.43%.
[0066] Example 1
[0067] This embodiment provides a method for enzymatic hydrolysis of lignocellulose, comprising the following steps:
[0068] Pretreatment: 15 parts by weight of lignocellulose powder, 0.5 parts by weight of additive, 1.5 parts by weight of choline chloride, 3 parts by weight of sodium sulfite and 85 parts by weight of deionized water are mixed evenly, and hydrothermally reacted at a temperature of 160° C. for 3 hours, and the reaction product is subjected to solid-liquid separation to obtain a first solid matrix and a pretreatment liquid, and the first solid matrix is washed with deionized water to neutrality, and then dried in an oven at 70° C. to obtain a second solid matrix; wherein the additive is acrylamide;
[0069] Enzymolysis: 5 parts by weight of the second solid matrix, 5 parts by volume of the pretreatment liquid and 95 parts by volume of acetic acid-sodium acetate buffer solution (pH 4.8, ion concentration 50 mmol / L) were mixed uniformly to obtain a first solution. 10 FPU / g of cellulase was added to the first solution based on the mass of the second solid matrix. The solution was placed in a shaker at a rotation speed of 150 rpm and a temperature of 50°C. After enzymolysis for 72 hours, an enzymolysis solution was obtained.
[0070] Examples 2-16 and Comparative Examples 1-4
[0071] Examples 2-16 and Comparative Examples 1-4 provide a method for enzymatic hydrolysis of lignocellulose, the differences between which and Example 1 are shown in Table 1.
[0072] Comparative Example 5
[0073] This comparative example provides an enzymatic hydrolysis method for lignocellulose, which differs from Example 5 only in that: during the enzymatic hydrolysis process, 5 parts by volume of the pretreatment liquid are replaced with 5 parts by volume of the first treatment liquid, wherein the first treatment liquid includes 0.5 parts by weight of SDS, 1.5 parts by weight of choline chloride, 3 parts by weight of sodium sulfite and 85 parts by weight of deionized water.
[0074] Comparative Example 6
[0075] This comparative example provides an enzymatic hydrolysis method for lignocellulose, which differs from Example 5 only in that: during the enzymatic hydrolysis process, 5 parts by volume of the pretreatment liquid are replaced by 5 parts by volume of the second treatment liquid; the second treatment liquid comprises 0.5 parts by weight of Tween 80, 1.5 parts by weight of choline chloride, 3 parts by weight of sodium sulfite and 85 parts by weight of deionized water.
[0076] Comparative Example 7
[0077] This comparative example provides an enzymatic hydrolysis method for lignocellulose, which differs from Example 5 only in that: during the enzymatic hydrolysis process, 5 parts by volume of the pretreatment liquid are replaced by 5 parts by volume of the third treatment liquid; the third treatment liquid comprises 0.5 parts by weight of CTAB, 1.5 parts by weight of choline chloride, 3 parts by weight of sodium sulfite and 85 parts by weight of deionized water.
[0078] Comparative Example 8
[0079] This comparative example provides an enzymatic hydrolysis method for lignocellulose, which differs from Example 5 only in that: during the enzymatic hydrolysis process, 5 parts by volume of the pretreatment liquid are replaced by 5 parts by volume of the fourth treatment liquid; the fourth treatment liquid comprises 1.5 parts by weight of choline chloride, 3 parts by weight of sodium sulfite and 85 parts by weight of deionized water.
[0080] Test Case
[0081] Enzyme hydrolysis rate: 1 ml of the enzyme hydrolysate of the embodiment and the comparative example was taken respectively, and centrifuged at a speed of 10000 rpm for 10 min. The supernatant was taken and the reducing sugar content was determined by the DNS method. The enzyme hydrolysis rate of the cellulase was calculated by the reducing sugar yield. Enzyme hydrolysis rate = reducing sugar mass × 0.9 / (substrate mass × cellulose mass fraction) × 100%. The calculation results are shown in Table 1.
[0082] Table 1: Various parameters and enzymolysis rate test results of the embodiments and comparative examples
[0083]
[0084]
[0085] Note: SDS is sodium dodecyl sulfate and CTAB is cetyltrimethylammonium bromide.
[0086] It can be seen from the experimental data in Table 1 that the enzymatic hydrolysis method of lignocellulose is used in the present disclosure to enzymatically hydrolyze lignocellulose, and the enzymatic hydrolysis rate of lignocellulose reaches more than 69%.
[0087] By comparing Examples 1-5, Example 8 and Comparative Examples 2-4, it can be seen that the type of additive will affect the enzymatic hydrolysis rate of lignocellulose. When the additive is an anionic surfactant, a cationic surfactant or a nonionic surfactant, the enzymatic hydrolysis rate of lignocellulose is lower than 58%.
[0088] By comparing Example 5 with Examples 8-10, it can be seen that, based on 100 parts by weight of lignocellulose, when the weight of the additive is 0.5-10 parts, the enzymatic hydrolysis rate of lignocellulose reaches more than 74%, indicating that based on 100 parts by weight of lignocellulose, when the weight of the additive is 0.5-10 parts, the enzymatic hydrolysis effect of lignocellulose is good, especially when the weight of the additive is 3-10 parts, the enzymatic hydrolysis effect of lignocellulose is better.
[0089] By comparing Example 5 with Examples 11-13, it can be seen that, based on 100 parts by weight of lignocellulose, when the weight of sodium sulfite is 5-100 parts, the enzymatic hydrolysis rate of lignocellulose is better, especially when it is 15-70 parts, the enzymatic hydrolysis effect of lignocellulose is better.
[0090] By comparing Example 5 with Examples 14-16, it can be seen that when the volume of the pretreatment liquid is 2-5% of the total volume of the pretreatment liquid and the buffer solution, the enzymatic hydrolysis rate of lignocellulose is 80.7-82.4%, indicating that when the volume of the pretreatment liquid is in the range of 2-5% of the total volume of the pretreatment liquid and the buffer solution, lignocellulose has a higher enzymatic hydrolysis rate.
[0091] By comparing Example 5 and Comparative Examples 5-8, it can be seen that when at least one additive selected from anionic surfactants, cationic surfactants and nonionic surfactants is used as the pretreatment liquid, the enzymatic hydrolysis rate of lignocellulose is lower than 69%, indicating that the pretreatment liquid disclosed in the present invention can significantly improve the enzymatic hydrolysis rate of lignocellulose.
[0092] Finally, it should be noted that the above embodiments are used to illustrate the technical solution of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present disclosure can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present disclosure.
Claims
1. A method for enzymatic hydrolysis of lignocellulose, characterized in that: The following steps are involved: Pretreatment: Mix lignocellulose, additives, choline chloride, sodium sulfite and water evenly, perform hydrothermal reaction at a temperature of 160-180°C, separate the reaction products into solid and liquid, and obtain a solid matrix and a pretreatment liquid; Enzymatic hydrolysis: the solid matrix, the pretreatment solution and the buffer solution are mixed evenly to obtain a first solution, cellulase is added to the first solution to perform enzymatic hydrolysis to obtain an enzymatic hydrolyzate; The additive is at least one of acrylamide, hydroxyethyl acrylate and a rare earth compound.
2. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: Based on 100 parts by weight of wood cellulose, the invention comprises the following components in parts by weight: 0.5-10 parts of additives, 5-15 parts of choline chloride, 5-100 parts of sodium sulfite and 400-800 parts of water.
3. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The rare earth compound is at least one of gallium trichloride, gallium oxide, and yttrium oxide.
4. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The hydrothermal reaction time is 2-4h.
5. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The ratio of the mass of the solid matrix to the total volume of the pretreatment solution and the buffer solution is 2g:100mL-10g:100mL.
6. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The volume of the pretreatment solution is 2-5% of the total volume of the pretreatment solution and the buffer solution.
7. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The enzymatic hydrolysis temperature is 40-60°C, the rotation speed is 100-200 rpm, and the time is 48-96 hours.
8. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The amount of the cellulase is 3-30 FPU / g based on the mass of the lignocellulose.
9. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The pH of the buffer solution is 4.5-6.0, and the ionic strength is 25-100 mmol / L.
10. The enzymatic hydrolysis method of lignocellulose according to claim 1, characterized in that: The wood cellulose is at least one of filter paper cellulose, microcrystalline cellulose, pine, eucalyptus, poplar, corn cob, corn stalk, wheat straw, bagasse and rice straw.