A preparation method of a composite material for removing fermentation inhibitors in acid hydrolysis of agricultural and forestry fibers

Abstract

The invention discloses a preparation method of a composite material for removing fermentation inhibitors in acid hydrolysis of agricultural and forestry fibers, belonging to the technical field of development and utilization of waste biomass resources. First, a phosphoric acid mixed pulp containing bamboo source residues is prepared from the crushed and screened bamboo source residues and phosphoric acid solution; calcium oxide or calcium hydroxide is added, mixed and homogenized to obtain a mixed pulp containing bamboo source residues and basic calcium phosphate, and then the mixed pulp is dried into powder; the powder is placed in a quartz tube for activation treatment to obtain a bamboo carbon-based material; then it is impregnated in a reducing agent solution and dried to obtain a composite material for removing fermentation inhibitors in acid hydrolysis of agricultural and forestry fibers. The composite material prepared by the invention has integrated synergistic effects such as adsorption, neutralization and reduction, and has the effect of removing fermentation inhibitors under various types of acidic conditions; moreover, the element distribution has good uniformity, good water dispersibility, good stability at room temperature storage, can be added to fluids and semi-fluids, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of development and utilization of waste biomass resources, and particularly relates to a method for preparing a composite material for removing acid hydrolysis fermentation inhibitors from agricultural and forestry fibers. Background Art

[0002] At present, the amount of forest biomass resources in China is about 350 million tons, and the comprehensive utilization rate of forest biomass is about 60%. The annual amount of agricultural straw resources in China is about 1 billion tons, and the comprehensive utilization rate is nearly 90%. However, the development of agricultural and forestry food and feed utilization technologies is slow, with high costs, poor stability, and generally small industrial scales. The high-value utilization technology of agricultural and forestry lignin resources urgently needs to be upgraded. Agricultural and forestry lignin is mainly composed of cellulose, hemicellulose, and lignin. Among them, hemicellulose can be degraded into small molecule sugars and oligosaccharides after acid hydrolysis, and cellulose can be hydrolyzed into glucose by cellulase, and then can be microbially transformed to prepare feed single-cell protein and amino acids; the unhydrolyzed cellulose component can be further fermented to prepare fiber compound feed with intestinal probiotic function. It is expected that by 2035, the energy feed gap in China will exceed 88 million tons, and the protein feed gap will exceed 124 million tons. It is urgent to develop new high-value resource feed technologies and innovate lignocellulose biorefinery technologies; developing agricultural and forestry biomass fermentation feed is of great strategic significance for ensuring China's food security and improving the effective utilization of agricultural and forestry residues.

[0003] Agroforestry fiber biorefining technology generally includes the following parts: saccharification pretreatment, removal of fermentation inhibitors, biological fermentation, separation and purification, etc. No matter what pretreatment and hydrolysis methods are adopted, it is difficult to completely avoid the generation of inhibitory compounds. Considering cost and efficiency, the sulfuric acid method is mainly used for saccharification pretreatment in China at present. However, harmful components such as aldehydic acids and phenols are easily generated during saccharification treatment with the sulfuric acid method. Therefore, it is necessary to remove fermentation inhibitors. The main methods for removing fermentation inhibitors include biological removal, water washing removal, alkalization treatment, adsorption filtration, etc. The water washing method is mostly used in industry. The above-mentioned fermentation inhibitor removal technologies have the disadvantages of cumbersome operation, high energy consumption, low efficiency, and high loss rate of fermentation substrates. Bamboo resources are a kind of renewable biomass, which grow fast, have high yields, and are widely planted. China is the richest in bamboo resources. The bamboo product industry in China has developed rapidly, and the output of bamboo processing waste is huge. Using bamboo processing waste as raw materials, bamboo-derived biomass carbon and its composite adsorption materials prepared by chemical activation often have advantages such as low cost and good performance. Biomass carbon can effectively remove harmful substances in feed, such as adsorbing mycotoxins and toxic phenolic acids, decolorizing and deodorizing, etc.; however, the adsorption performance of biomass carbon for polar compounds is limited, and the adsorption efficiency in complex medium systems may fluctuate greatly, restricting its application scenarios and efficiency. Basic calcium phosphate can be formed by the reaction of phosphoric acid with excessive calcium oxide or calcium hydroxide, and can be regarded as a mixture of calcium phosphate and calcium hydroxide. It has good biocompatibility and slow release properties, and can slowly neutralize acidic components in the medium. Basic calcium phosphate is extremely easy to precipitate, so its dispersibility is poor, affecting the removal efficiency of acidic components in the medium. Adding reducing agents can effectively counteract microbial inhibitors such as free radicals and aldehyde compounds in acid hydrolysis solutions, but reducing agents are easily oxidized and often have poor stability, and cannot play a continuous scavenging role.

[0004] To solve the above problems, the present invention uses bamboo-derived residues as raw materials, and basic calcium phosphate and reducing agents as activators, and develops a preparation method of bamboo-derived carbon-based composite materials that can be widely applied to the removal of fermentation inhibitors in acid hydrolysis of lignocellulose by using high-temperature activation, multi-stage homogenization combined with impregnation compounding preparation technology. This is beneficial to realizing the integrated removal of fermentation inhibitors, effectively improving the fermentation conversion efficiency after fiber saccharification, and then increasing the microbial conversion yield, thus having far-reaching significance for realizing the high-value and high-efficiency feed utilization of agroforestry lignocellulose and forming a new quality productivity technology reserve of "fiber sugar production replacing grain" for ensuring national food security. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a preparation method of composite materials for removing fermentation inhibitors in acid hydrolysis of agroforestry fibers; another technical problem to be solved by the present invention is to provide the use of composite materials for removing fermentation inhibitors in acid hydrolysis of agroforestry fibers.

[0006] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A method for preparing a composite material for removing fermentation inhibitors from agroforestry fibers by acid hydrolysis, comprising the following steps:

[0008] (1) Prepare a phosphoric acid mixed pulp containing bamboo source residues from the crushed and screened bamboo source residues and phosphoric acid solution; then add calcium oxide or calcium hydroxide, fully mix and react and homogenize to obtain a mixed pulp containing bamboo source residues and calcium hydrogen phosphate, and then dry the mixed pulp into powder;

[0009] (2) Activate the powder in step (1) in a quartz tube to obtain a dark brown powder, which is a bamboo source carbon-based material containing calcium hydrogen phosphate;

[0010] (3) Immerse the bamboo source carbon-based material containing calcium hydrogen phosphate in step (2) in a reducing agent solution, dry it, and the obtained brown powder is a composite material that can be used to remove fermentation inhibitors from agroforestry fibers by acid hydrolysis.

[0011] In step (1), the mass ratio of the bamboo source residues to the phosphoric acid solution is 1:0.1 - 0.3; the soaking time of the bamboo source residues in the phosphoric acid solution is 2 - 12 h.

[0012] The bamboo source residues in step (1) include bamboo processing residues and bamboo shoot husks; the particle size after crushing and screening is 0.02 - 2 nm; the solid content of the prepared phosphoric acid mixed pulp containing bamboo source residues is 12% - 22%; the pH of the phosphoric acid mixed pulp containing bamboo source residues is 1.5 - 3.5.

[0013] In step (1), the mass ratio of the phosphoric acid mixed pulp containing bamboo source residues to calcium oxide or calcium hydroxide is 1:0.1 - 0.5; the stirring temperature of the mixed pulp and calcium oxide is 60 - 100 °C; the stirring time is 2 - 6 h.

[0014] The solid content of the mixed pulp containing bamboo source residues and calcium hydrogen phosphate prepared in step (1) is 13% - 25%; the pH of the mixed pulp containing bamboo source residues and calcium hydrogen phosphate is 7.5 - 10.5; the rotation speed of the high-speed shearing treatment is 5000 - 20000 rpm; the shearing time is 5 - 30 min; the pressure of the high-pressure homogenization treatment is 15000 - 25000 PSI; the homogenization treatment time is 2 - 15 min.

[0015] The conditions for the activation treatment in step (2) are to heat up to 340 - 420 °C at a heating rate of 5 - 15 °C / min and keep warm for 1 - 6 h.

[0016] In step (3), the mass ratio of the bamboo-derived carbon-based material containing calcium hydrogen phosphate to the reducing agent solvent is 1:0.05 - 0.15; the type of the reducing agent is sodium sulfite or ammonium sulfite; the mass fraction of the reducing agent solution is 1% - 5%.

[0017] The composite material for removing acid hydrolysis fermentation inhibitors of agricultural and forestry fibers prepared by the described method.

[0018] The application of the described composite material for removing acid hydrolysis fermentation inhibitors of agricultural and forestry fibers in the removal of acid hydrolysis fermentation inhibitors of agricultural and forestry fibers.

[0019] The fiber acid includes inorganic acid, organic acid or mixed acid hydrolysis solution.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The present invention uses the bamboo-derived waste biomass resources which are rich in source and low in price as raw materials, and the production process is simple and easy to implement, which is conducive to the high-value utilization of waste biomass resources.

[0022] (2) The preparation method of the present invention is simple, environmentally friendly and has good process stability. By further processing the bamboo-derived residues, controlling the addition amount of calcium hydrogen phosphate generated by the reaction of phosphoric acid and calcium oxide or calcium hydroxide, adjusting the ratio of the mixture of the bamboo-derived residues and calcium hydrogen phosphate, and adjusting the content of the reducing agent by the impregnation method, the optimal compounding is achieved; the biomass carbon material has a high specific surface area and porosity, has good uniform loading performance for calcium hydrogen phosphate and the reducing agent, and the prepared composite material has integrated synergistic effects such as adsorption, neutralization and reduction, and has the effect of removing fermentation inhibitors under various types of acidic conditions; the composite material has good element distribution uniformity, good water dispersibility and good stability at normal temperature storage, and can be added to fluids and semi-fluids, and has a wide application range.

[0023] (3) The main raw materials used in the present invention meet the requirements of food and feed additive raw materials. The prepared composite material has rich phosphorus and calcium contents, and also has functions such as phosphorus and calcium nutrition supplementation, and can be applied to fields such as food and feed industries. The present invention also has good application prospects in fields such as the development and utilization of waste biomass resources, biorefining, and fermentation industry. Description of the Drawings

[0024] Figure 1 It is the scanning electron microscope image of the composite material for removing acid hydrolysis fermentation inhibitors of agricultural and forestry fibers prepared in Example 1 of the present invention;

[0025] Figure 2 It is the surface element distribution map of the composite material for removing acid hydrolysis fermentation inhibitors of agricultural and forestry fibers prepared in Example 1 of the present invention;

[0026] Figure 3 It is the energy spectrum elemental analysis diagram of the composite material prepared in Example 1 of the present invention for removing acid hydrolysis fermentation inhibitors from agricultural and forestry fibers. Detailed implementation manners

[0027] The present invention will be further illustrated below in conjunction with specific embodiments. The embodiments are implemented on the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0028] Example 1

[0029] (1) Slowly add 10 g of bamboo powder with a particle size of 0.05 - 1 nm after crushing and screening into 100 mL of 3% phosphoric acid solution, stir well and soak for 6 h to obtain a phosphoric acid mixed slurry containing bamboo source residues with a pH of about 2 and a solid content of about 12%; then add 4 g of calcium hydroxide to the phosphoric acid mixed slurry containing bamboo source residues, stir and react at 90 °C for 4 h, then perform high-speed shearing treatment at a shearing speed of 15000 rpm for 10 min, and then perform high-pressure homogenization treatment at a pressure of 20000 PSI for 10 min to obtain a mixed slurry containing bamboo source residues and calcium basic phosphate with a solid content of about 15%. Further dry the mixed slurry into powder, about 17 g;

[0030] (2) Place the obtained 17 g of powder in a quartz tube, heat it to 380 °C at a heating rate of 5 °C / min for activation treatment for 3 h to obtain about 9.5 g of dark brown powder, which is the bamboo source carbon-based material containing calcium basic phosphate;

[0031] (3) Immerse the obtained 9.5 g of bamboo source carbon-based material containing calcium basic phosphate in 50 mL of 2.5% sodium sulfite solution, vacuum dry it at 50 °C to constant weight, and the obtained about 10.7 g of brown powder is the composite material that can be used to remove acid hydrolysis fermentation inhibitors from agricultural and forestry fibers.

[0032] Example 2

[0033] (1) Slowly add 50 g of bamboo shoot shell powder with a particle size of 0.1 - 2 mm after crushing and screening into 300 mL of 5% phosphoric acid solution, stir well and soak for 12 h to obtain a phosphoric acid mixed slurry containing bamboo source residues with a pH value of about 1.5 and a solid content of about 19%; then add 30 g of calcium oxide to the phosphoric acid mixed slurry containing bamboo source residues, stir and react at 100 °C for 6 h, then perform high-speed shearing treatment at a shearing speed of 20000 rpm for 30 min, and then perform high-pressure homogenization treatment at a pressure of 25000 PSI for 15 min to obtain a mixed slurry containing bamboo source residues and calcium basic phosphate with a solid content of about 25%. Further dry the mixed slurry into powder, about 95 g;

[0034] (2) Place the obtained 95 g of powder in a quartz tube and heat it to 420 °C at a heating rate of 15 °C / min for activation treatment for 6 h to obtain approximately 55 g of dark brown powder, which is the bamboo-derived carbon-based material containing calcium hydrogen phosphate;

[0035] (3) Place the obtained 55 g of bamboo-derived carbon-based material containing calcium hydrogen phosphate in 165 mL of 5% potassium sulfite solution for sufficient impregnation, and vacuum dry it at 60 °C until constant weight. The obtained approximately 63.2 g of brown powder is the composite material that can be used for removing the inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers.

[0036] Example 3

[0037] (1) Slowly add 5 g of bamboo powder with a particle size of 0.02 - 0.2 mm after crushing and screening into 20 mL of 2.5% phosphoric acid solution, stir well and soak for 2 h to obtain a phosphoric acid mixed slurry containing bamboo-derived residues with a pH value of about 3 and a solid content of about 22%; then add 0.5 g of calcium hydroxide to the phosphoric acid mixed slurry containing bamboo-derived residues, stir and react at 60 °C for 2 h, then perform high-speed shearing treatment at a shearing speed of 5000 rpm for 5 min, and then perform high-pressure homogenization treatment at a pressure of 15000 PSI for 2 min to obtain a mixed slurry containing bamboo-derived residues and calcium hydrogen phosphate with a solid content of about 24%. Further dry the mixed slurry into powder, about 6 g;

[0038] (2) Place the obtained 6 g of powder in a quartz tube and heat it to 340 °C at a heating rate of 5 °C / min for activation treatment for 1 h to obtain approximately 2 g of dark brown powder, which is the bamboo-derived carbon-based material containing calcium hydrogen phosphate;

[0039] (3) Place the obtained 2 g of bamboo-derived carbon-based material containing calcium hydrogen phosphate in 10 mL of 1.1% ammonium sulfite solution for sufficient impregnation, and vacuum dry it at 40 °C until constant weight. The obtained approximately 2.1 g of brown powder is the composite material that can be used for removing the inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers.

[0040] Example 4

[0041] (1) Slowly add 1 kg of bamboo shoot shell powder with a particle size of 0.05 - 2 mm after crushing and screening into 5 L of 5% phosphoric acid solution, stir well and soak for 8 h to obtain a phosphoric acid mixed slurry containing bamboo-derived residues with a pH value of about 2 and a solid content of about 21%; then add 250 g of calcium oxide to the phosphoric acid mixed slurry containing bamboo-derived residues, stir and react at 80 °C for 4 h, then perform high-speed shearing treatment at a shearing speed of 15000 rpm for 10 min, and then perform high-pressure homogenization treatment at a pressure of 20000 PSI for 15 min to obtain a mixed slurry containing bamboo-derived residues and calcium hydrogen phosphate with a solid content of about 24%. Further dry the mixed slurry into powder, about 1.5 kg;

[0042] (2) Place the obtained 1.5 kg of powder into multiple quartz tubes respectively, heat it to 400 °C at a heating rate of 10 °C / min for activation treatment for 5 h, and obtain about 0.7 kg of dark brown powder, which is the bamboo-derived carbon-based material containing calcium hydrogen phosphate;

[0043] (3) Place the obtained 0.7 kg of bamboo-derived carbon-based material containing calcium hydrogen phosphate into 3.5 L of 2% sodium sulfite solution for full impregnation, and dry it to constant weight under vacuum at 45 °C. The obtained about 0.77 kg of brown powder is the composite material that can be used for removing the acid hydrolysis fermentation inhibitors of agricultural and forestry fibers.

[0044] Example 5

[0045] (1) Slowly add 200 g of bamboo powder with a particle size of 0.02 - 1 mm after crushing and screening into 1.6 L of 1% phosphoric acid solution, stir well and soak for 8 h to obtain a phosphoric acid mixed slurry containing bamboo-derived residues with a pH value of about 3.5 and a solid content of about 12%; then add 20 g of calcium hydroxide to the phosphoric acid mixed slurry containing bamboo-derived residues, stir and react at 70 °C for 3 h, then perform high-speed shearing treatment at a shearing speed of 10000 rpm for 15 min, and then perform high-pressure homogenization treatment at a pressure of 25000 PSI for 10 min to obtain a mixed slurry containing bamboo-derived residues and calcium hydrogen phosphate with a solid content of about 13%. Further dry the mixed slurry into powder, about 236 g;

[0046] (2) Place the obtained 236 g of powder into a quartz tube, heat it to 360 °C at a heating rate of 10 °C / min for activation treatment for 4 h, and obtain about 76 g of dark brown powder, which is the bamboo-derived carbon-based material containing calcium hydrogen phosphate;

[0047] (3) Place the obtained 76 g of bamboo-derived carbon-based material containing calcium hydrogen phosphate into 250 mL of 3% potassium sulfite solution for full impregnation, and dry it to constant weight under vacuum at 55 °C. The obtained about 83 g of brown powder is the composite material that can be used for removing the acid hydrolysis fermentation inhibitors of agricultural and forestry fibers.

[0048] Example 6

[0049] For the composite materials obtained in the above Examples 1 - 5 for removing the acid hydrolysis fermentation inhibitors of agricultural and forestry fibers, particle size distribution analysis (including average particle size, particle size distribution coefficient, tested by a laser particle size analyzer) was carried out respectively, and the results are shown in Table 1.

[0050] Table 1 Comparison table of particle size distribution of the composite materials obtained in Examples 1 - 5 in water

[0051] Index Example 1 Example 2 Example 3 Example 4 Example 5 Particle size distribution (μm) 0.2-12.2 0.1-12.1 0.2-16.4 0.2-12.3 0.1-12.9 Average particle size (μm) 6.2 6.1 8.3 6.2 6.5 Particle size distribution coefficient 0.297 0.304 0.413 0.322 0.350

[0052] Examples 1-5 are specifically characterized by: having good dispersibility in water, with a particle size distribution range of 0.1 - 18.5 μm and a distribution coefficient range of 0.296 - 0.413. From the particle size distribution test results in Table 1 data, the average particle size in ascending order is Example 2 ≈ 1 ≈ 4 > 5 > 3, and the distribution coefficient in ascending order is Example 1 ≈ 2 > 4 > 5 > 3, indicating that Examples 1 and 2 have better dispersibility in water than other examples.

[0053] Examples 1-5 also show: good stability during storage at room temperature, with no color change, no agglomeration, and no deterioration within six months when stored naturally and sealed at room temperature; among which, Example 1 was Figure 1 and Figure 3 through scanning electron microscopy and energy dispersive spectroscopy analysis, it was found that calcium hydrogen phosphate and reducing agent are mainly loaded on the bamboo-derived carbon-based material in an attached or embedded manner, and the elemental distribution uniformity is good.

[0054] Example 7

[0055] For the composite materials obtained from the above Examples 1-5 for removing fermentation inhibitors from agroforestry fibers during acid hydrolysis, their application in scavenging fermentation inhibitors in agroforestry residue acid hydrolysates includes using colorimetry to determine the content of fermentation inhibitors in the hydrolysate, including the content of Maillard reaction products and phenolic compounds. Among them, the absorbance value (OD 420 ) measured under the condition of 420 nm is used to evaluate the content of Maillard reaction products, and the absorbance value (OD 420 ) is positively correlated with the content of Maillard reaction products; the absorbance value (OD 280 ) measured under the condition of 280 nm is used to evaluate the content of phenolic compounds, and the absorbance value (OD 280 ) is positively correlated with the content of phenolic compounds; the absorbance values (after appropriate dilution) of the hydrolysates without adding the composite materials obtained from Examples 1-5 (hereinafter all referred to as: non-added control) and the composite materials obtained from Examples 1-5 applied to different agroforestry fiber hydrolysates are shown in Tables 2-5 below.

[0056] Table 2 Comparison table of absorbance values of fermentation inhibitors of the composite materials obtained from Examples 1-5 applied to corn stover sulfuric acid hydrolysate (0.6% sulfuric acid, hydrolyzed at 120 °C for 1 h, solid content 5%)

[0057]

[0058] Table 3 Comparison table of absorbance values of fermentation inhibitors of the composite materials obtained from Examples 1-5 applied to bamboo shoot shell sulfuric acid hydrolysate (0.75% sulfuric acid, hydrolyzed at 110 °C for 2 h, solid content 6.5%)

[0059]

[0060] Table 4 Comparison table of absorbance values of fermentation inhibitors in the composite materials obtained in Examples 1-5 applied to Caragana korshinskii sulfuric acid hydrolysis solution (hydrolyzed with 0.5% sulfuric acid at 130 °C for 0.8 h, solid content 4%)

[0061]

[0062]

[0063] Table 5 Comparison table of absorbance values of fermentation inhibitors in the composite materials obtained in Examples 1-5 applied to Populus davidiana sulfuric acid hydrolysis solution (hydrolyzed with 0.3% sulfuric acid at 105 °C for 3 h, solid content 2.5%)

[0064]

[0065] Examples 1-5 specifically show that for the fermentation inhibitors in the hydrolysis solution, including Maillard reaction products and phenolic compounds, they all have good removal effects. From the absorbance values (OD 420 ) and absorbance values (OD 280 ) in the test results of Tables 2-5, the order of the values from small to large is Example 2 ≈ 1 > 4 > 5 > 3, which means that Examples 1 and 2 have better removal effects on the fermentation inhibitors in the hydrolysis solution, including Maillard reaction products and phenolic compounds, than other examples.

[0066] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a composite material for removing fermentation inhibitors in acid hydrolysis of agricultural and forestry fibers, characterized in that: It includes the following steps: (1) Prepare a phosphoric acid mixed pulp containing bamboo source residues from the crushed and sieved bamboo source residues and phosphoric acid solution; then add calcium oxide, fully mix and react, and homogenize to obtain a mixed pulp containing bamboo source residues and calcium hydrogen phosphate, and then dry the mixed pulp containing bamboo source residues and calcium hydrogen phosphate into powder; the soaking time of the bamboo source residues in the phosphoric acid solution is 2-12 h; the bamboo source residues include bamboo processing residues and bamboo shoot shells; the particle size of the crushed and sieved bamboo source residues is 0.02-2 mm; the pH of the phosphoric acid mixed pulp containing bamboo source residues is 1.5-3.5; the stirring temperature of the phosphoric acid mixed pulp containing bamboo source residues and calcium oxide is 60-100 °C, and the stirring time is 2-6 h; the pH of the mixed pulp containing bamboo source residues and calcium hydrogen phosphate is 7.5-10.5; the rotation speed of the high-speed shearing treatment is 5000-20000 rpm; the shearing time is 5-30 min; the pressure of the high-pressure homogenization treatment is 15000-25000 PSI; the homogenization treatment time is 2-15 min; (2) Place the powder obtained in step (1) in a quartz tube for activation treatment to obtain a dark brown powder, which is a bamboo source carbon-based material containing calcium hydrogen phosphate; the conditions of the activation treatment are to heat up to 340-420 °C at a heating rate of 5-15 °C / min and keep warm for 1-6 h; (3) Immerse the bamboo source carbon-based material containing calcium hydrogen phosphate obtained in step (2) in a reducing agent solution, dry it, and the obtained brown powder is a composite material that can be used for removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers; the types of the reducing agent solution are sodium sulfite or ammonium sulfite.

2. The composite material for removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers prepared by the method according to claim 1.

3. Application of the composite material for removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers according to claim 2 in removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers.

4. Application of the composite material for removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers according to claim 3 in removing inhibitors in the acid hydrolysis fermentation of agricultural and forestry fibers, wherein the agricultural and forestry fibers acid includes inorganic acid, organic acid or mixed acid hydrolysis solution.

Images