CN117737158A - Pretreatment method for densification of calcium hydroxide and hydrogen peroxide combined with lignocellulose raw material - Google Patents
Pretreatment method for densification of calcium hydroxide and hydrogen peroxide combined with lignocellulose raw material Download PDFInfo
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- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 title claims abstract description 34
- 239000000920 calcium hydroxide Substances 0.000 title claims abstract description 34
- 229910001861 calcium hydroxide Inorganic materials 0.000 title claims abstract description 34
- 238000000280 densification Methods 0.000 title claims abstract description 23
- 239000002994 raw material Substances 0.000 title claims abstract description 22
- 238000002203 pretreatment Methods 0.000 title claims abstract description 19
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Abstract
The invention discloses a pretreatment method for densification of calcium hydroxide and hydrogen peroxide combined with lignocellulose raw material. Adding calcium hydroxide and hydrogen peroxide into crushed lignocellulose raw materials, uniformly mixing, and then adding into a densification machine for densification, or adding the calcium hydroxide, the hydrogen peroxide and the lignocellulose raw materials into the densification machine together for densification to obtain densified lignocellulose. According to the invention, calcium hydroxide and hydrogen peroxide are added simultaneously in the densification process of the lignocellulose raw material to destroy the lignocellulose structure, so that the material can be prevented from mildew in the transportation and storage processes, and a certain pretreatment effect is achieved. The invention can reach over 85 percent of enzymatic saccharification efficiency under the conditions of 0.075-g calcium hydroxide addition and 0.03-g hydrogen peroxide addition per gram of straw, and has good fermentation performance under the condition of no water toxicity elution.
Description
Technical Field
The invention belongs to the technical field of biorefinery, and relates to a pretreatment method for densification of calcium hydroxide and hydrogen peroxide and lignocellulose raw materials together.
Background
The fermentation production of fuel ethanol has high product yield and is green and environment-friendly, and has become the main attack direction of biomass resource development. The fermentation production of ethanol from starch and carbohydrate feedstocks has a long history of development and relatively mature process technology. Lignocellulosic biomass has also been used to attempt conversion to ethanol. Lignocellulosic biomass is a clean renewable resource, and development and utilization of the biomass are attracting more and more attention. Pretreatment is an important step for processing biomass, and the traditional pretreatment modes comprise alkali treatment, acid treatment, ionic liquid treatment, steam explosion pretreatment, ultrasonic pretreatment and the like, so that the problems of severe pretreatment conditions, large consumption of reagents, large amount of produced toxic degradation products and the like are mostly existed. Therefore, development of a novel pretreatment technology with high efficiency, low cost and few toxic degradation products is a problem to be solved urgently.
Document 1 reports a conventional Alkaline Hydrogen Peroxide (AHP) pretreatment method by adding 0.125gH to corn stalks 2 O 2 Per gram of straw, pH was adjusted to 11.5 with 5M sodium hydroxide, treated at 22deg.C for 48h, and enzymatically hydrolyzed at 10% solids to yield 75% glucose and 71% xylose (Goutamide B, suzana C, tongjun L, et al. Scale-Up and Integration of Alkaline Hydrogen Peroxide Pretreatment, enzymatic Hydrolysis, and Ethanolic Fermentation [ J)]Biotechnology and Bioengineering,2012, 109:922-931.). However, the conventional alkaline hydrogen peroxide pretreatment has some problems, such as high hydrogen peroxide consumption, low enzymolysis immobilization amount, high concentration of generated inhibitor, poor enzymolysis effect and the like.
Disclosure of Invention
The invention aims to provide a pretreatment method for densification of calcium hydroxide and hydrogen peroxide together with lignocellulose raw material. Compared with the densification treatment of lignocellulose and calcium hydroxide and the traditional alkaline hydrogen peroxide pretreatment, the method greatly reduces the addition amount of the calcium hydroxide and the hydrogen peroxide, realizes the pretreatment of high-solid biomass, and in addition, the hydrogen peroxide is a green reagent and is decomposed into oxygen and water in the reaction process, so that the sugar conversion rate of lignocellulose is improved.
The technical scheme for realizing the purpose of the invention is as follows:
the pretreatment method for densification of calcium hydroxide and hydrogen peroxide and lignocellulose raw material is specifically as follows:
adding calcium hydroxide and hydrogen peroxide into crushed lignocellulose raw materials, uniformly mixing and then adding into a densification machine for densification, or adding calcium hydroxide, hydrogen peroxide and lignocellulose raw materials into the densification machine together for densification to obtain densified lignocellulose.
Further, the lignocellulosic feedstock is a lignocellulosic biomass feedstock conventionally used in the biorefinery field, such as wheat straw, corn straw, rice straw, barley straw, sorghum straw, soybean straw, forestry waste, recycled wood pulp fiber, wood chips, cork, hardwood, aquatic plants, animal manure, and the like.
Further, the dosage of calcium hydroxide is 7.5% -15% of the mass of the lignocellulose raw material, the dosage of hydrogen peroxide is 3% -10.0% of the mass of the lignocellulose raw material, and the dosage of water is 30% -70% of the mass of the lignocellulose raw material.
Further, the densified lignocellulose is in the form of a rod, a granule or a block, and the bulk density of the densified lignocellulose is more than or equal to 200kg/m 3 Preferably 200 to 1500kg/m 3 。
Further, the further treatment modes are treatment modes which are conventionally used in the biorefinery field, such as soaking, insolation, high-temperature heating, microwave, ultrasonic crushing, hydrothermal treatment, acidic pretreatment, alkaline pretreatment and the like.
Preferably, the further treatment mode is high-temperature heating, the high-temperature heating temperature is 100-200 ℃, and the high-temperature heating time is 15-180min.
Further, the densified lignocellulose is directly subjected to biodegradation conversion, or is subjected to biodegradation conversion after being stored for a period of time, or is subjected to biodegradation conversion after being further processed, or is subjected to biodegradation conversion after being stored for a period of time, and is subjected to biodegradation conversion, wherein the biodegradation conversion is one or a combination of more of enzymatic hydrolysis and microbial fermentation.
Further, the enzyme used in the enzymatic hydrolysis is selected from one or more combinations of cellulases, hemicellulases, pectinases and xylanases, and the fermenting microorganism employed in the microbial fermentation is selected from one or more combinations of yeasts, bacteria and molds.
Further, the solid content of the densified lignocellulose in the enzyme hydrolysis process is more than 15%, preferably 20% -35%.
Further, the biodegradable conversion product is sugar, alcohol, acetone, organic acid, aliphatic hydrocarbon, grease, protein, amino acid, enzyme, antibiotic, vitamin, antibody or biogas.
Compared with the prior art, the invention has the following advantages:
(1) Improving biomass digestibility: the treated biomass is more susceptible to degradation by microorganisms or enzymes, which means that it can be more easily converted into fermentable sugars (such as glucose and xylose) or other valuable chemicals.
(2) The inhibitor concentration produced was low: conventional AHP pretreatment produces large amounts of inorganic salts and small molecule materials such as phenols, organic acids and oxides. The method has the advantages that the dosage of the hydrogen peroxide is low, the concentration of the generated inhibitor is low, and the influence on the subsequent enzymolysis and fermentation is obviously reduced.
(3) High-solid-load enzymolysis and fermentation: according to the invention, biomass is densified, so that the density of the biomass is greatly increased, enzymolysis and fermentation can be realized under the condition of high solid load, and commercialization of cellulosic ethanol is possible.
(4) Saving chemical reagent: the low amount of alkali and hydrogen peroxide required in the present invention, which reduces industrial costs, also means that less acid is required to adjust the pH.
Drawings
FIG. 1 is a graph showing the effect of hydrogen peroxide addition on the enzymatic hydrolysis sugar conversion rate of corn stover treated by the present method during pretreatment;
FIG. 2 is a graph showing the effect of calcium hydroxide addition on the enzymatic hydrolysis sugar conversion rate of corn stover treated by the method during pretreatment;
FIG. 3 is a graph showing the increase of the conversion rate of corn stalk enzymolysis sugar with the increase of the solid content and time of steam sterilization treatment;
FIG. 4 is a graph showing the change of concentration of corn stalk enzyme hydrolysis sugar treated by the method along with the increase of the immobilized amount;
FIG. 5 is a graph showing the change of the enzymolysis conversion rate of corn stalks treated by the method along with the increase of the solid content;
FIG. 6 is a graph showing the fermentation results of corn stalks treated by the method under different solid supports;
FIG. 7 is a graph comparing the enzymatic hydrolysis effects of DLCA (ch-hp) and DLCA (ch) pretreatment.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the accompanying drawings and preferred embodiments, but the scope of the present invention is not limited to the following examples.
All terms of art used hereinafter are defined as commonly understood by one skilled in the art unless otherwise defined.
Unless otherwise specifically indicated, reagents, materials, equipment, and the like used in the present invention are all available commercially or may be prepared by existing methods.
The following abbreviations are used in the examples below:
DLC (ch-hp) -CS: calcium hydroxide is combined with hydrogen peroxide to densify pretreated corn stalk particles;
DLCA (ch-hp) -CS: DLC (ch-hp) -CS after steam sterilization;
DLCA (ch) -CS: and (5) densifying the corn straw particles by the calcium hydroxide after further steam sterilization.
Example 1
This example compares the enzymatic hydrolysis effect of DLCA (ch-hp) -CS at various hydrogen peroxide additions, as follows:
(1) DLC (ch-hp) pretreatment process: firstly, 0.1g/g of calcium hydroxide is added into crushed corn straws, then hydrogen peroxide is added into the corn straws, the addition amounts of the calcium hydroxide and the hydrogen peroxide are respectively 0, 0.01, 0.02, 0.03, 0.04 and 0.05g/g of the corn straws, the mixture is mixed for 2 hours and then densified in a densification machine, DLC (ch-hp) -CS particles are obtained, and the moisture is dried to about 15 percent.
(2) The further pretreatment process comprises the following steps: the DLC (ch-hp) -CS particles obtained in the step 1 are placed into a high-temperature sterilization pot with a solid content of 35%, the temperature is set to 121 ℃ and the time is 30min, and DLCA (ch-hp) -CS is obtained, and the water content is dried to about 15%.
(3) Enzymatic hydrolysis process: the DLCA (ch-hp) -CS treated with different hydrogen peroxide concentrations obtained above was subjected to enzymatic hydrolysis of 3% substrate (based on total system mass) in a 10g system, and was added with Cellic CTec3HS cellulase and citric acid-sodium citrate buffer, and placed in a shaking incubator (set at 250rpm, 50 ℃) for hydrolysis for 24 hours at an enzyme dosage of 15mgprotein/g glucose.
And (3) after carrying out enzyme hydrolysis on the straws treated under different conditions, measuring the concentration of sugar in hydrolysate, and calculating the sugar conversion rate. FIG. 1 is a graph showing the effect of different hydrogen peroxide addition on glucan and xylan conversion, with increasing hydrogen peroxide addition, the glucan and xylan conversion increasing gradually, because the greater the degree of damage to the straw with increasing hydrogen peroxide addition. At an addition of 0.03g/g, the conversion of glucan was 91.38%, the conversion of xylan was 70.40%, and the increase in the addition of hydrogen peroxide was not significant. Compared with the treatment without hydrogen peroxide (only calcium hydroxide and straw densification treatment), the glucan conversion rate of adding 0.03g of hydrogen peroxide per g of straw is improved by 13% (from 78% to 91%, and the improvement is remarkable and great).
Example 2
This example compares the enzymatic hydrolysis effect of DLCA (ch+hp) -CS at various calcium hydroxide additions, as follows:
(1) DLC (ch-hp) pretreatment process: firstly, adding calcium hydroxide into corn stalks, wherein the adding amount is 0, 0.025, 0.05, 0.075, 0.1 and 0.125g/g corn stalks respectively, then adding 0.03g/g hydrogen peroxide into crushed corn stalks, uniformly mixing, densifying in a granulator to obtain DLC (ch-hp) -CS particles, and airing the DLC (ch-hp) -CS particles until the moisture reaches about 15%.
(2) The further pretreatment process comprises the following steps: the DLC (ch-hp) -CS particles obtained in the step 1 are placed into a high-temperature sterilization pot with a solid content of 35%, the temperature is set to 121 ℃ and the time is 30min, and DLCA (ch-hp) -CS is obtained, and the water content is dried to about 15%.
(3) Enzymatic hydrolysis process: different oxyhydrogen obtained abovePerforming enzyme hydrolysis of 3% substrate (based on total system) in 10g system with DLCA (ch-hp) -CS treated with calcium conversion concentration, adding Cellic CTec3HS cellulase and citric acid-sodium citrate buffer solution, culturing in shake incubator (setting rotation speed of 250rpm, temperature of 50% ○ C) The enzyme amount was 15mgprotein/g glucan and the hydrolysis time was 24 hours.
And (3) after carrying out enzyme hydrolysis on the straws treated under different conditions, measuring the concentration of sugar in hydrolysate, and calculating the sugar conversion rate. FIG. 2 shows that the fixed hydrogen peroxide addition is 0.03g/g, the conversion rate of glucan and xylan is 83.38% and 62.24% respectively when the calcium hydroxide addition is 0.075g/g, and it can be seen that the corn stalk enzymolysis conversion rate is lower when the calcium hydroxide addition is lower than 0.075g/g, and the conversion rate of glucan and xylan can be improved to a certain extent by increasing the calcium hydroxide addition when the calcium hydroxide addition is higher than 0.075 g/g.
Example 3
This example compares the effect of further heat treatment immobilization and time on the enzymatic hydrolysis effect of DLCA (ch-hp) -CS, as follows:
(1) DLC (ch-hp) pretreatment process: firstly, adding calcium hydroxide into corn stalks with the addition of 0.075g/g, then adding hydrogen peroxide with the addition of 0.03g/g into crushed corn stalks, uniformly mixing, and densifying in a granulator to obtain DLC (ch-hp) -CS particles, and airing the DLC particles until the moisture content reaches about 15%.
(2) The further pretreatment process comprises the following steps: placing DLC (ch-hp) -CS particles obtained in the step 1 into a high-temperature sterilization pot with the solid content of 25%, 30% and 35%, wherein the temperature is set to 121 ℃ and the time is 30min; for different reaction times, the fixed solid content is 35 percent, the fixed solid content is put into a sterilizing pot, the temperature is set to 121 ℃, the reaction time is 30, 60 and 90 minutes, DLCA (ch-hp) -CS is obtained, and the water content is dried to about 15 percent.
(3) Enzymatic hydrolysis process: the DLCA (ch-hp) -CS obtained above was subjected to enzymatic hydrolysis of 3% substrate (based on total system) in 10g system, cellic CTec3HS cellulase and citric acid-sodium citrate buffer were added, and cultured in a shaking incubator (set at a rotation speed of 250rpm, at a temperature of 50% ○ C) The enzyme dosage is 15mg protein/g glucosan, and the hydrolysis time is 24 hoursWhen (1).
And (3) after carrying out enzyme hydrolysis on the straws treated under different conditions, measuring the concentration of sugar in hydrolysate, and calculating the sugar conversion rate. Fig. 3 is a graph showing the change of the conversion rate of corn stalk enzymatic hydrolysis sugar with the increase of the solid content and time of steam sterilization treatment, and it can be seen that the conversion rate increases with the increase of the reaction time, and the effect of different solid content and reaction time on the conversion rate is not obvious in general, but the increase of the solid content and the decrease of the reaction time have a certain reduction of the economic load, so that 35% of solid content and the reaction time of 30min are selected as further treatment conditions.
Example 4
This example shows the high substrate enzymatic hydrolysis of DLC (ch-hp) -CS, i.e., DLCA (ch-hp) -CS, treated at 121℃for 30min at 35% immobilization, with different immobilization rates, as follows:
(1) DLCA (ch-hp) -CS pretreatment procedure was as in example 3.
(2) Enzymatic hydrolysis process: the high substrate enzyme hydrolysis solid loads were set to 25%, 30% and 35% (based on the total mass of the material and water), the CTec3HS enzyme amount was 20mg protein/g glucan, and the culture was carried out in a shake incubator (set at 250rpm, at 50 ℃) for 72 hours. In order to obtain higher enzymolysis sugar concentration, 25%, 30% and 35% of solid load are selected to explore the enzymolysis effect of DLCA (ch-hp) -CS, and in order to improve the enzymolysis conversion rate, the method of batch feeding is adopted in the embodiment, the initial solid load is 20%, 5% of each fed material is fed for 1 time, two times of 30% fed and three times of 35% fed.
As can be seen from FIG. 4, the enzymatic hydrolysis sugar concentration of DLCA (ph) -CS increased with increasing solids loading, with 25% solids glucose concentration, xylose concentration, total sugar concentration of 82.58g/L, 37.86g/L, 111.60g/L, respectively, and 30% solids concentration of 111.60g/L, 47.61g/L, 155.69g/L, respectively, and glucan conversion still exceeding 80% (FIG. 5). When the immobilization amount was increased to 35%, the glucose concentration, xylose concentration, and total sugar concentration were increased to 132.05g/L, 61.10g/L, and 193.15g/L. The high-concentration sugar obtained by high-solid-load enzymolysis shows that the raw material treated by the method has better industrialized application potential.
Example 5
The experimental analysis of the ethanol production effect of fermentation in the bioconversion process of DLCA (ch-hp) -CS is carried out in the embodiment, and the experimental analysis is specifically as follows:
(1) DLCA (ch-hp) -CS pretreatment procedure was as in example 4.
(2) Synchronous saccharification and fermentation process: the high substrate enzyme hydrolysis immobilization amounts are set to be 25%, 30% and 35% (based on the total mass), the material is first pre-hydrolyzed, the pre-hydrolysis process is carried out in a constant temperature shaking table at 50 ℃ and a rotating speed of 250rpm, after the pH of DLCA (ch-hp) -CS material is adjusted to 4.8 by sulfuric acid solution, 20mg of CTec3-HS cellulase of protein/g glucan is added. The materials are all added in a fed-batch mode within 12 hours, then the pH of the pre-hydrolyzed slurry is regulated to about 5.5 by sulfuric acid solution, a nitrogen source is added, xylose yeast strains are inoculated into the pre-hydrolyzed slurry, the OD600 value of the initial strains is 2, fermentation is carried out in a constant-temperature shaking table at the temperature of 30 ℃ and the rotating speed of 150rpm, samples are taken from the reaction system every 24 hours, and the concentration of sugar and ethanol in the sample solution is detected by HPLC.
This example explores the high substrate hydrolysate fermentation effect of DLCA (ch-hp) -CS. As shown in the fermentation results of a, b and c in FIG. 6, the glucose concentration is basically 0g/L when the fermentation is carried out for 24 hours, the xylose is basically fully utilized under the condition of 25 percent of solid loading when the fermentation is carried out for 96 hours, the xylose is slightly remained under the condition of 30 percent of solid loading, and the xylose is remained to a certain extent under the condition of 35 percent of solid loading, so that the fermentation effect is better as a whole. The ethanol concentrations after 96h fermentation under 25%, 30% and 35% immobilization are 48.40g/L, 59.31g/L and 65.63g/L respectively. The results show that DLCA (ch-hp) pretreatment has good fermentation performance, and can realize effective utilization of corn stalks.
Example 6
This example is a study of the generation of inhibitors at different immobilization levels of DLCA (ch-hp) -CS, and is specifically as follows:
(1) DLCA (ch-hp) -CS pretreatment procedure was as in example 4.
(2) Enzymatic hydrolysis process: the enzyme hydrolysis immobilization amount of the high substrate is set to be 25%, 30% and 35% (based on the material)And total mass of water), CTec3HS enzyme amount of 20mg protein/g glucan, and culturing in shake incubator (setting rotation speed at 250rpm, temperature at 50% ○ C) The hydrolysis time was 72 hours.
(3) The obtained hydrolysate is detected by Agilent high performance liquid chromatograph, and the determination of the total phenol concentration in the sample solution is carried out according to Folin-Ciocalteu colorimetric method: the standard substances are 0, 0.1, 0.25, 0.5, 0.75 and 1g/L vanillin solution, and the sample to be tested is diluted by a certain multiple to ensure that the total phenol concentration is lower than 1 g/L. Taking 100 mu L of standard substances and samples to be tested with different concentrations into two groups of centrifuge tubes, adding 3mL of water and 250 mu LFOlin-Ciocalteu reagent into each centrifuge tube, and after 5min, adding 750 mu LNa into each centrifuge tube 2 CO 3 The solution (20%, w/w) and 900. Mu.L of distilled water were added separately to give a total volume of 5mL of liquid. And (3) placing the centrifuge tube in a shaking table at the constant temperature of 22 ℃ for culturing for 2 hours, and detecting the absorbance of the sample to be detected and the standard substance by an ultraviolet spectrophotometer under the condition of 760 nm.
This example explores the inhibition of DLCA (ch-hp) -CS during pretreatment. Corn straw is composed of cellulose, hemicellulose and lignin, and after being treated by chemical reagents and high-temperature and high-pressure steam, each component of the corn straw is damaged to different degrees and can be degraded into micromolecular substances including acetic acid (from hemicellulose acetyl), phenolic compounds and the like. These too high concentrations inhibit subsequent enzymatic hydrolysis and fermentation, as can be seen from Table 1, the inhibitors after DLCA (ch-hp) pretreatment are mainly acetic acid and phenolic substances, since calcium hydroxide pretreatment can effectively remove acetyl side chains of hemicellulose and convert into acetic acid, and phenolic substances are lignin degradation products. As the solids loading increased from 25% to 35%, the acetic acid concentration increased from 3.76g/L to 5.95g/L, the total phenol concentration increased from 2.04g/L to 2.33g/L, and the phenolics concentration was relatively low. And inhibitors such as furfural and 5-hydroxymethylfurfural which are common in other pretreatment methods are not generated in the pretreatment method. The above inhibitor analysis also fully illustrates the reason for the high fermentability of the material after pretreatment by the present method.
TABLE 1 concentration of inhibitor produced by pretreatment of corn stover by the present method at different solids levels
Example 7
This example investigated the comparison of enzymatic hydrolysis effects of DLCA (ch-hp) and DLCA (ch) pretreatment at 35% immobilization, as follows:
(1) DLCA (ch-hp) -CS pretreatment procedure was as in example 4.
(2) Firstly, adding calcium hydroxide into corn straws with the addition of 0.15g/g, uniformly mixing, and then densifying in a granulator to obtain DLC (ch) -CS particles, and airing until the moisture is about 15%; the obtained DLC (ch) -CS particles were put into a high-temperature sterilization pot for further heat treatment, the immobilization was 35%, the temperature was set at 121℃and the time was 30min. The treated material was DLCA (ch) -CS.
(3) Enzymatic hydrolysis process: the DLCA (ch-hp) -CS and DLCA (ch) -CS obtained above were subjected to enzymatic hydrolysis of 35% substrate (based on total system) in 150g system, cellic CTec3HS cellulase was added, and the mixture was placed in a shaking incubator (set at 250rpm, temperature: 50. Smallc.) and incubated at 15mg protein/g glucose for 24 hours.
This example investigated the enzymatic hydrolysis effects of DLCA (ch-hp) and DLCA (ch) pretreatment at 35% immobilization and evaluated the advantages of DLCA (ch-hp). As can be seen from FIG. 7, DLCA (ch-hp) pretreated glucose, xylose and total sugar concentrations were 132.05g/L, 61.01g/L, 193.15g/L, respectively, while DLCA (ch) pretreated glucose, xylose and total sugar concentrations were 125.73g/L, 45.52g/L, 171.28g/L, respectively. Under the same pretreatment conditions and the same enzymolysis conditions, DLCA (ch-hp) has higher enzymolysis effect than DLCA (ch) pretreatment, the total sugar concentration is increased by 22g/L (the lifting amplitude is 12.8%), and the DLCA (ch-hp) has better enzymolysis effect than DLCA (ch) pretreatment.
Claims (10)
1. A pretreatment method for densification of calcium hydroxide and hydrogen peroxide together with lignocellulose raw material, which is characterized by comprising the following specific steps:
adding calcium hydroxide and hydrogen peroxide into crushed lignocellulose raw materials, uniformly mixing and then adding into a densification machine for densification, or adding calcium hydroxide, hydrogen peroxide and lignocellulose raw materials into the densification machine together for densification to obtain densified lignocellulose.
2. The pretreatment method according to claim 1, wherein the lignocellulose raw material is wheat straw, corn straw, rice straw, barley straw, sorghum straw, soybean straw, forestry waste, recovered wood pulp fiber, wood chips, cork, hardwood, aquatic plants or animal feces.
3. The pretreatment method according to claim 1, wherein the amount of calcium hydroxide is 7.5 to 15% by mass of the lignocellulose raw material, the amount of hydrogen peroxide is 3 to 10.0% by mass of the lignocellulose raw material, and the amount of water is 30 to 70% by mass of the lignocellulose raw material.
4. The pretreatment method according to claim 1, wherein the densified lignocellulose is in the form of a rod, a granule or a block, and the densified lignocellulose has a bulk density of 200kg/m or more 3 Preferably 200 to 1500kg/m 3 。
5. The pretreatment method according to claim 1, wherein the further treatment is soaking, insolation, high temperature heating, microwave, ultrasonic disruption, hydrothermal treatment, acidic pretreatment or alkaline pretreatment.
6. The pretreatment method according to claim 1, wherein the further treatment is high temperature heating at a temperature of 100 ℃ to 200 ℃ for 15 to 180min.
7. The pretreatment method of claim 1, wherein the densified lignocellulose is directly subjected to a biodegradation conversion, or is subjected to a biodegradation conversion after a period of storage, or is subjected to a biodegradation conversion after a further treatment, or is subjected to a further treatment after a period of storage, and is subjected to a biodegradation conversion, said biodegradation conversion being one or more of a combination of enzymatic hydrolysis and microbial fermentation.
8. The pretreatment method according to claim 7, wherein the enzyme used in the enzymatic hydrolysis is selected from one or more combinations of cellulase, hemicellulase, pectinase and xylanase, and the fermenting microorganism used in the microbial fermentation is selected from one or more combinations of yeast, bacteria and mold.
9. The pretreatment method according to claim 1, wherein the amount of densified lignocellulose immobilized during the enzymatic hydrolysis is 15% or more, preferably 20% -35%.
10. The pretreatment method according to claim 1, wherein the biodegradable conversion product is sugar, alcohol, acetone, organic acid, aliphatic hydrocarbon, grease, protein, amino acid, enzyme, antibiotic, vitamin, antibody or biogas.
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