A plant fiber material disassembling reagent, a plant fiber material disassembling conversion method and a glucose preparation method

Abstract

The present application relates to the technical field of chemical engineering, and discloses a kind of plant fiber material disassembly reagent and the disassembly conversion method and preparation method of plant fiber material glucose.The disassembly reagent component of the present application includes ChCl-Gly and basic substance, and the mass percentage of DES-Gly is 20-80wt%, and the mass percentage of basic substance is 2-7wt%.The disassembly reagent and disassembly conversion method of the present application can be used for the preparation of glucose.In the disassembly process, the present application can efficiently remove lignin, further improve the exposure degree of cellulose and hemicellulose, provide a better substrate for enzymatic reaction, thereby greatly improving the glucose yield.The lignin removal rate of the present application reaches 78.41%, and the glucose yield can reach 96.11% at most.When the cellulase addition amount is only 8FPU / g, the glucose yield reaches 95.42%, which significantly reduces the cost of biochemical conversion.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering technology, and more specifically, to a plant fiber material dismantling reagent, a method for dismantling and converting plant fiber materials, and a method for preparing glucose. Background Technology

[0002] In recent years, with the gradual depletion of traditional fossil fuels and the aggravation of environmental pollution, clean, green, and renewable energy have become a global research hotspot. Plant fiber materials have received widespread attention due to their abundant resources, high renewability, and low pollution. Wheat straw is an important agricultural waste, rich in lignocellulose, and has high-value conversion potential. However, due to the complex structure and high resistance to degradation of plant fiber materials, their efficient utilization still faces many challenges.

[0003] Enzymatic hydrolysis of plant fiber materials to produce glucose is a high-value conversion method. Lignocellulose in plant fiber materials is mainly composed of cellulose, hemicellulose, and lignin. These components are tightly bound together by covalent bonds (such as ester and ether bonds) and non-covalent interactions (such as hydrogen bonds), forming a dense three-dimensional structure. This gives plant fiber materials high resistance to enzymatic hydrolysis and structural stability, severely limiting their conversion efficiency in fields such as biofuels and chemical synthesis. Therefore, improving the accessibility of plant fiber materials and reducing the enzymatic hydrolysis barrier are key issues that urgently need to be addressed in the field of biomass utilization. Furthermore, the high cost of cellulase also limits the high-value conversion of wheat straw.

[0004] Eutectic solvents (DES) have been widely used in the pretreatment of lignocellulose in recent years due to their environmental friendliness and easy recyclability. Their working principle is to disrupt the three-dimensional structure of lignocellulose, dissolving some of the lignin, thereby improving cellulose accessibility and enzymatic hydrolysis efficiency. However, DES such as ChCl-Gly (choline chloride-glycerol) are used in large quantities in pretreatment, typically with a solvent-to-straw mass ratio between 10:1 and 20:1, increasing production costs. Simultaneously, the high viscosity of the solvent affects mass transfer, reducing pretreatment efficiency. For example, patent CN106086106A uses a multi-hydrogen-bond donor DES to pretreat corn straw; when the solvent-to-straw mass ratio is 20:1, the glucose yield is only 76.5%, indicating limited conversion efficiency. Furthermore, most existing methods require high reaction temperatures (above 120°C) and long processing times (above 80 minutes), resulting in excessive energy consumption. Moreover, existing technologies are usually optimized for single raw materials, failing to consider the characteristics of multiple biomass feedstocks.

[0005] Existing technology 201880035442.6 provides a method for producing nanocellulose materials, employing a ternary eutectic solvent as a swelling agent to dissolve or expand cellulose, thereby improving its conversion efficiency. However, this method is mainly suitable for bleached chemical pulps (containing ≥90wt% cellulose or ≤5wt% lignin, or even ≤1wt%), whose raw materials have already undergone chemical pretreatment to remove most of the lignin and hemicellulose. Furthermore, this method involves harsh pretreatment conditions, long processing times, and high energy consumption. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, such as large solvent consumption, large enzyme addition, high processing temperature and long processing time, inability to handle multiple plant fiber materials, and low dismantling and conversion efficiency, this invention provides a plant fiber material dismantling reagent.

[0007] Another object of the present invention is to provide an application of a plant fiber material disintegration reagent;

[0008] Another objective of this invention is to provide a method for dismantling and converting plant fiber materials;

[0009] Another object of the present invention is to provide a method for preparing glucose.

[0010] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0011] A plant fiber material disintegration reagent comprises ChCl-Gly and an alkaline substance; wherein the ChCl-Gly is a mixture of choline chloride and glycerol.

[0012] Preferably, the component further includes water.

[0013] Furthermore, in the plant fibrous material disintegration reagent, the mass percentage of DES-Gly is 20-80 wt%, and the mass percentage of alkaline substances is 2-7 wt%.

[0014] Preferably, the mass percentage of the alkaline substance is 5-7 wt%.

[0015] Furthermore, the alkaline substance includes organic bases and inorganic bases.

[0016] Preferably, the organic base includes 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DUB).

[0017] Preferably, the inorganic base includes sodium hydroxide and potassium hydroxide.

[0018] Furthermore, the ChCl-Gly is composed of choline chloride and glycerol mixed in a molar ratio of 1:(1-5).

[0019] Preferably, ChCl-Gly is a mixture of choline chloride and glycerol in a molar ratio of 1:2.

[0020] Furthermore, the mass percentage of lignin in the plant fiber material is less than 25%.

[0021] Preferably, the lignin content in the plant fiber material is greater than 15% by mass.

[0022] Preferably, the plant fibrous material is an unprocessed natural plant material.

[0023] Preferably, the plant fiber material includes grasses and broad-leaved wood.

[0024] Preferably, the gramineous plant material includes wheat straw, rice straw, and sugarcane bagasse; the broadleaf wood material includes poplar and eucalyptus.

[0025] An application of a plant fiber material disintegration reagent for the production of glucose.

[0026] A method for dismantling and converting plant fiber materials, wherein the plant fiber material is prepared by reacting with a dismantling reagent.

[0027] Preferably, the method for dismantling and converting plant fiber materials includes the following steps: mixing and reacting the pulverized plant fiber materials in a plant fiber material dismantling reagent, and completing the dismantling by vacuum filtration; and completing the conversion by adding cellulase to the obtained solid components and reacting.

[0028] Furthermore, the mass ratio of plant fiber material to plant fiber material disintegration reagent is 1:(10-15).

[0029] Preferably, the mass ratio of plant fiber material to plant fiber material disintegration reagent is 1:15.

[0030] Furthermore, the reaction conditions are: reaction at 80–120°C for 10–80 min.

[0031] Preferably, the reaction conditions are a temperature of 100–120°C.

[0032] Preferably, the reaction conditions are 60–80 min.

[0033] Preferably, cellulase and buffer solution are added to the obtained solid component for reaction.

[0034] Preferably, the amount of cellulase added is 4–20 FPU / g (matrix).

[0035] Preferably, the amount of cellulase added is 8–20 FPU / g (matrix).

[0036] Preferably, the pH value of the buffer solution is 3 to 5.

[0037] Preferably, the pH value of the buffer solution is 4.8.

[0038] Preferably, the buffer solution comprises a mixture of citric acid monohydrate and trisodium citrate dihydrate.

[0039] Preferably, the mass-to-volume ratio of the obtained solid component to the buffer solution is 1 g: 40-60 mL.

[0040] Preferably, the mass-to-volume ratio of the obtained solid component to the buffer solution is 1 g: 50 mL.

[0041] Preferably, the enzymatic hydrolysis is performed at a temperature of 40–60°C for a time of 0–72 h.

[0042] Preferably, the enzymatic hydrolysis temperature is 50°C.

[0043] A method for preparing glucose, wherein the glucose is prepared by reacting the plant fiber material with a disintegrating reagent.

[0044] Existing technologies using eutectic solvents (ChCl-Gly) for the pretreatment and conversion of fibrous materials cannot be directly applied to unprocessed plant materials. Furthermore, they suffer from problems such as high solvent consumption, high viscosity, high pretreatment temperature, and excessively long treatment times, resulting in high dismantling costs and unsatisfactory dismantling efficiency. In addition, during enzymatic hydrolysis, the large amount of cellulase added results in very low glucose content, significantly increasing the cost of biomass conversion.

[0045] One of the inventive aspects of this application lies in the synergistic effect of ChCl-Gly and alkaline substances. The addition of ChCl-Gly can significantly reduce the degradation rate of cellulose and hemicellulose, thereby reducing carbohydrate loss caused by excessively high temperatures or strong solvent action. This not only improves dismantling efficiency but also enables effective pretreatment of wheat straw at lower temperatures and in a shorter time, thus significantly reducing energy consumption and costs associated with pretreatment.

[0046] The introduction of alkaline substances primarily addresses the problem of low lignin removal rates in existing technologies. Lignin is one of the most difficult components to degrade in plant fiber materials, and it inhibits the enzymatic hydrolysis of cellulase, severely affecting the exposure of cellulose. This invention promotes the dissolution and removal of lignin through alkaline substances, releasing it from the structure of cellulose and hemicellulose. This effectively removes lignin, reduces the binding strength between lignin and cellulose / hemicellulose, and thus significantly improves the accessibility of cellulose.

[0047] Another significant innovation of this invention is that by limiting the ratio of the eutectic solvent to the alkaline substance, the amount of cellulase added is reduced. Through the technical solution proposed in this invention, the amount of cellulase added during enzymatic hydrolysis can be significantly reduced while still maintaining a high glucose yield.

[0048] By limiting the concentration of alkaline substances, the amount of ChCl-Gly added, and the reaction temperature and time, this invention can efficiently remove lignin during the disassembly process, further increasing the exposure of cellulose and hemicellulose, providing a better matrix for the enzymatic hydrolysis reaction, thereby significantly improving the glucose yield.

[0049] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0050] 1. Significantly improves glucose yield. This invention improves lignin removal rate and cellulose accessibility by limiting the ratio of ChCl-Gly and alkaline substances. The glucose yield of this invention can reach up to 96.11%.

[0051] 2. Reduced cellulase usage. By limiting the ratio of eutectic solvent to alkaline substance and reaction conditions, this invention reduces the amount of cellulase required by 60% while still maintaining a high glucose yield. With a cellulase addition of only 8 FPU / g (matrix), the glucose yield reaches 95.42%, significantly reducing the cost of biochemical conversion.

[0052] 3. Improved lignin removal rate. This invention effectively improves the lignin removal rate to 78.41% through the synergistic effect of ChCl-Gly and alkaline substances.

[0053] 4. Suitable for a variety of plant fiber materials. This invention is not only applicable to wheat straw, but can also be widely applied to other plant fiber materials such as rice straw, sugarcane bagasse, and poplar wood, achieving high lignin removal rates and glucose yields in all cases. The technical solution of this invention makes the disassembly and conversion method compatible with a variety of plant fiber materials, improving the versatility and applicability of the technology. Attached Figure Description

[0054] Figure 1 Images of the plant fiber materials in Examples 1 and 17-19 before and after disassembly. Detailed Implementation

[0055] The present invention will be further illustrated below with specific embodiments, but these embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0056] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0057] The wheat straw used in the following examples was obtained from Hebei Yigao Biofuel Co., Ltd. through air drying, crushing and sieving. The cellulose content was 36.46%, hemicellulose was 17.69% and lignin was 21.10%.

[0058] The bagasse in the following examples was obtained from Maoming, Guangdong, through air drying, crushing and sieving. The cellulose content was 38.18%, hemicellulose was 18.5%, and lignin was 18.79%.

[0059] The rice straw in the following examples was obtained from Donghai, Jiangsu Province, through air drying, crushing and sieving. The cellulose content was 36.82%, hemicellulose was 17.69%, and lignin was 16.04%.

[0060] The poplar wood in the following examples was obtained from Dezhou, Shandong Province, through air drying, crushing and sieving. The cellulose content was 43.08%, hemicellulose was 15.97%, and lignin was 23.65%.

[0061] In the following examples, ChCl-Gly is prepared by mixing choline chloride and glycerol in a molar ratio of 1:2.

[0062] 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) was commercially available.

[0063] The buffer solution is a mixture of citric acid monohydrate and trisodium citrate dihydrate, with a pH of 4.8.

[0064] Example 1

[0065] 1. Preparation of disassembly reagents: Mix ChCl-Gly, DBN and water in a mass ratio of 20:5:75.

[0066] 2. Wheat straw dismantling: Crush wheat straw to 40-60 mesh to obtain crushed wheat straw. Take 15g of crushed wheat straw and 225g of dismantling reagent and place them in a closed reactor equipped with thermocouples. Mix them and react at 100℃ for 60min. Immediately cool the mixture to 30℃ with cooling water and perform vacuum filtration to obtain the filtrate and a cellulose-rich solid component. Collect the solid component and store it in a refrigerator for later use.

[0067] 3. Enzymatic hydrolysis: Take 1.0g of cellulose-rich solid component (matrix) (based on absolute dryness) and mix it with 50.0mL of buffer solution. Place the mixture in a 150mL Erlenmeyer flask and carry out the enzymatic hydrolysis reaction of the cellulose-rich solid component and buffer solution at 50℃ and 150rpm. Add 20FPU / g (matrix) of cellulase and react for 72h.

[0068] Examples 2-6

[0069] The technical solutions of Examples 2 to 6 are similar to those of Example 1, and the differences are shown in Table 1.

[0070] Table 1

[0071] The mass ratio of ChCl-Gly, DBN and water Example 2 20：3：77 Example 3 20：7：73 Example 4 40：5：55 Example 5 60：5：35 Example 6 80：5：15

[0072] Examples 7-12

[0073] The technical solutions of Examples 7 to 12 are similar to those of Example 1, and the differences are shown in Table 2.

[0074] Table 2

[0075] Disassembly reaction conditions Example 7 80℃, 60min Example 8 120℃, 60min Example 9 100℃, 10min Example 10 100℃, 20min Example 11 100℃, 40min Example 12 100℃, 80min

[0076] Examples 13-16

[0077] The technical solutions of Examples 13 to 16 are similar to those of Example 1, and the differences are shown in Table 3.

[0078] Table 3

[0079] Cellulose addition (FPU / g) Example 13 4 Example 14 8 Example 15 10 Example 16 15

[0080] Example 17

[0081] The difference between Example 17 and Example 1 is that wheat straw is replaced with sugarcane bagasse, and the disintegration reagent DBN is replaced with DBU. Other conditions and steps are the same.

[0082] Example 18

[0083] The difference between Example 18 and Example 1 is that wheat straw is replaced with rice straw, and the disintegration reagent DBN is replaced with NaOH, while other conditions and steps are the same.

[0084] Example 19

[0085] The difference between Example 19 and Example 1 is that wheat straw is replaced with poplar wood, and the disassembly reagent DBN is replaced with KOH, while other conditions and steps are the same.

[0086] Comparative Example 1

[0087] The difference between Comparative Example 1 and Example 1 is that in the wheat straw dismantling reagent, ChCl-Gly, DBN and water were mixed in a mass ratio of 0:5:95, while other conditions and steps were the same.

[0088] Comparative Example 2

[0089] The difference between Comparative Example 1 and Example 1 is that in the wheat straw dismantling reagent, ChCl-Gly, DBN and water were mixed in a mass ratio of 20:0:80, while other conditions and steps were the same.

[0090] Comparative Example 3

[0091] The difference between Comparative Example 3 and Example 1 is that in the preparation of the wheat straw dismantling reagent, ChCl-Gly, DBN and water were mixed in a mass ratio of 20:1:79, while other conditions and steps were the same.

[0092] Comparative Example 4

[0093] The difference between Comparative Example 4 and Example 1 is that the disassembly temperature was adjusted to 30°C during the disassembly process, while other conditions and steps were the same.

[0094] Comparative Example 5

[0095] The difference between Comparative Example 5 and Example 1 is that the disassembly temperature was adjusted to 60°C during the disassembly process, while other conditions and steps were the same.

[0096] Detection methods

[0097] Collect the supernatant of the enzymatically digested sample and determine the glucose concentration using high-performance liquid chromatography (HPLC). HPLC conditions: KS-801 column, flow rate 0.4 mL / min, column temperature 60℃.

[0098] The formula for calculating glucose yield is as follows:

[0099]

[0100] N is the measured glucose concentration (g / L);

[0101] V represents the volume of the enzymatic hydrolysis system (L);

[0102] 0.9 is the coefficient for the conversion of glucose to cellulose;

[0103]

[0104] Analysis and Explanation

[0105] The results in Table 4 were analyzed. In Comparative Example 1, when ChCl-Gly was not added to the dissociation reagent, cellulose and hemicellulose degradation was severe, lignin removal rate was low, and glucose yield was low. In Comparative Examples 2 and 3, when no alkaline substance was added to the dissociation reagent or too little was added, the lignin removal rate was only 10.89%, which seriously affected enzymatic hydrolysis, affected the accessibility of cellulose, and led to a significant reduction in glucose yield. The above results indicate that ChCl-Gly is mainly used to inhibit cellulose / hemicellulose degradation, while DBN mainly improves the lignin removal rate. The two must be mixed in a certain proportion in the dissociation reagent to exert a synergistic effect and improve glucose yield. In Comparative Example 4, at a dissociation reaction temperature of 30℃, lignin was almost not removed, the enzymatic hydrolysis efficiency was extremely low, and the glucose yield was only 34.02%. In Comparative Example 5, at a dissociation reaction temperature of 60℃, the lignin removal rate increased to 14.35%, but it was still low, resulting in a glucose yield of only 43.09%. This indicates that excessively low temperature will significantly affect lignin removal, thereby reducing glucose yield.

[0106] The method for dismantling and converting plant fiber materials provided by this invention achieves a lignin removal rate of up to 78.41% and a glucose yield of up to 97.91% (Example 17). However, by adding 4 FPU / g cellulase during the enzymatic hydrolysis stage, the glucose yield can still reach 80.36%; by slightly increasing the addition amount to 8 FPU / g, the glucose yield can reach 95.42%. The method of this invention significantly reduces the amount of cellulase added, effectively reducing production costs. In the method provided by this invention, the addition amount of ChCl-Gly is reduced by 80%, and the addition amount of cellulase is reduced by 60 wt%, enabling efficient conversion of plant fiber materials under mild conditions.

[0107] Table 4. Product composition analysis of the examples and comparative examples.

[0108]

[0109] In addition, from Figure 1 As can be seen, the plant fibers before disassembly are dry and compact, containing high levels of lignin and hemicellulose, which limits cellulose accessibility. After disassembly treatment using the method of this invention, the solid components become looser, and the exposure of cellulose increases significantly, providing better conditions for the subsequent enzymatic hydrolysis process. Through the synergistic effect of eutectic solvents and alkaline substances, the three-dimensional network structure of the plant fiber material is successfully disrupted, lignin is removed, and cellulose availability is enhanced, providing favorable conditions for subsequent enzymatic hydrolysis and further improving enzymatic hydrolysis efficiency and glucose yield.

[0110] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A plant fiber material disintegration reagent, characterized in that, Its components are ChCl-Gly, an alkaline substance and water; the ChCl-Gly is a mixture of choline chloride and glycerol; in the plant fiber material dismantling reagent, the mass percentage of the alkaline substance is 5wt%~7wt%; the alkaline substance is an organic base, namely 1,5-diazabicyclo[4.3.0]non-5-ene or 1,8-diazabicyclo[5.4.0]undec-7-ene.

2. The plant fiber material disintegration reagent according to claim 1, characterized in that, The ChCl-Gly is composed of choline chloride and glycerol mixed in a molar ratio of 1:(1~5).

3. The plant fiber material disintegration reagent according to claim 1, characterized in that, The mass percentage of lignin in the plant fiber material is less than 25%.

4. The application of a plant fiber material disintegration reagent according to any one of claims 1 to 3, characterized in that, Used to break down plant fibers to produce glucose.

5. A method for dismantling and converting plant fiber materials, characterized in that, The plant fiber material is prepared by reacting with the plant fiber material disintegration reagent according to any one of claims 1 to 3; the disintegration and conversion method of the plant fiber material includes the following steps: placing the pulverized plant fiber material in the plant fiber material disintegration reagent for mixing and reaction, and completing the disintegration by vacuum filtration; adding cellulase to the obtained solid component and reacting to complete the conversion; the reaction conditions are 100-120℃ for 60-80 min; the amount of cellulase added is 8-20 FPU / g.

6. The method for dismantling and converting plant fiber materials according to claim 5, characterized in that, The mass ratio of plant fiber material to plant fiber material disintegration reagent is 1:(10~15).

7. A method for preparing glucose, characterized in that, The method comprises the following steps: mixing and reacting the pulverized plant fiber material with the plant fiber material disintegration reagent according to any one of claims 1 to 3, and completing the disintegration by vacuum filtration; adding cellulase to the obtained solid component and reacting to complete the conversion; the reaction conditions are 100-120℃ for 60-80 min; and the amount of cellulase added is 8-20 FPU / g.

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