阅读说明：本技术 用热水结合绿液预处理提高竹材酶解糖化效率的方法 (Method for improving enzymolysis saccharification efficiency of bamboo wood by combining hot water with green liquor pretreatment ) 是由 骆莲新 王绪崇 朱秋晓 张胜 王婷婷 于 2021-09-14 设计创作，主要内容包括：本发明公开了用热水结合绿液预处理提高竹材酶解糖化效率的方法,取风干竹材经热水预处理、然后再进行绿液预处理,再进行盘磨,最后进行纤维素酶酶解糖化。本方法可大大提高竹材的酶解糖化效率,纤维素的酶解效率最高可达到96.65％。使用本方法得到的糖可用于制取工业乙醇,从而提高竹子的经济效益,扩大了应用范围,并且随着效率的提高,还可以节约能源。(The invention discloses a method for improving the enzymolysis saccharification efficiency of bamboo wood by combining hot water with green liquor pretreatment. The method can greatly improve the enzymolysis saccharification efficiency of the bamboo wood, and the highest enzymolysis efficiency of the cellulose can reach 96.65 percent. The sugar obtained by the method can be used for preparing industrial ethanol, thereby improving the economic benefit of bamboo, expanding the application range and saving energy along with the improvement of efficiency.)

1. A method for improving the enzymolysis saccharification efficiency of bamboo wood is characterized in that air-dried bamboo wood is taken and sequentially subjected to hot water pretreatment and green liquor pretreatment, then disc grinding is carried out, and finally cellulase enzymolysis saccharification is carried out.

2. The method for improving the bamboo enzymatic saccharification efficiency of claim 1, wherein the hot water pretreatment is to add hot water into the bamboo, and the temperature is kept at 120 ℃ for 75 min.

3. The method for improving the bamboo enzymatic saccharification efficiency of claim 2, characterized in that in the hot water pretreatment, the ratio of the absolutely dry bamboo to the hot water is 1: 6 g/mL.

4. The method for improving the bamboo enzymatic saccharification efficiency of claim 1, characterized in that the green liquor is prepared by blending green liquor of a paper mill, wherein 135.60g/L sodium carbonate, 22.13g/L sodium hydroxide and 25.10g/L sodium sulfide.

5. The method for improving the bamboo enzymatic saccharification efficiency as claimed in claim 1, characterized in that the green liquor pretreatment, the solid-to-liquid ratio of oven-dried bamboo to cooking liquor is 1: 6 g/mL.

6. The method for improving the bamboo enzymatic saccharification efficiency of claim 1, characterized in that the cooking liquor is a mixed liquor of green liquor and water, wherein the addition amount of the green liquor is 10% -20% of the oven-dried bamboo quality by total alkali, and the balance is water.

7. The method for improving bamboo enzymatic saccharification efficiency of claim 1, wherein the treatment temperature of green liquor pretreatment is 140-160 ℃, and the heat preservation time is 75 min.

8. The method for improving the enzymatic saccharification efficiency of bamboo wood as claimed in claim 1, wherein the activity of cellulase is 128FPU/g, and the dosage of cellulase is 15-20 FPU/g oven-dried bamboo wood.

9. The method for improving the enzymatic saccharification efficiency of bamboo wood according to claim 1, wherein the enzymatic saccharification by cellulase is carried out under the conditions that the pH is 4.5-5.0, the temperature is 50-60 ℃, and the rotating speed of a water bath shaker is 150 r/min.

Technical Field

The invention relates to the field of biomass clean energy, in particular to a method for improving bamboo enzymolysis saccharification efficiency by using hot water combined with green liquor pretreatment.

Background

Along with the development of economy in China, the problem of energy shortage is increasingly prominent, the national requirements on environmental protection are more and more strict, and the search for clean energy capable of replacing fossil fuels is reluctant. Therefore, a large number of scientific researchers focus on renewable biomass, and the fuel ethanol produced by the biomass is environment-friendly and can relieve the energy shortage problem. Bamboo resources are abundant in China, but because bamboo fibers are not as good as wood fibers, the utilization rate of the pulping and papermaking field is relatively low. However, the cellulose content of the fermented sugar can approximately reach 40 percent, and the fermented sugar has good advantages in the aspect of preparing the fermentable sugar. However, because the structure of bamboo is compact, cellulase is difficult to enter the non-pretreated bamboo and is difficult to contact cellulose, so the enzymolysis saccharification efficiency is extremely low.

The prior pretreatment methods mainly comprise a physical method, a chemical method, a biological method, a physical and chemical combined method and the like, wherein the most applied method is the chemical method, and mainly comprises dilute acid pretreatment, hot water pretreatment, alkali pretreatment, organic solvent pretreatment, ionic liquid pretreatment and the like, a large amount of acid-soluble lignin appears in the acid pretreatment, the reabsorption of the lignin can be caused to block the enzymolysis of cellulose, the cost of the organic solvent and the ionic liquid pretreatment is higher, the yield of enzymolysis reducing sugar of each hundred grams of raw materials at the present stage is below 50%, and the enzymolysis saccharification efficiency is not high. And some green liquor pretreatment methods directly use green liquor, and when the green liquor pretreatment condition reaches a certain degree, the effect is not obviously increased.

Disclosure of Invention

The invention provides a method for improving the bamboo enzymolysis saccharification efficiency by combining hot water with green liquor pretreatment in order to further improve the enzymolysis efficiency of cellulose in a bamboo raw material by cellulase and save energy consumption and the usage amount of the cellulase in the pretreatment process.

The technical scheme for solving the technical problems is as follows:

the method for improving the enzymolysis saccharification efficiency of the bamboo wood by combining hot water with green liquor pretreatment comprises the steps of taking the air-dried bamboo wood, sequentially carrying out hot water pretreatment and green liquor pretreatment, then carrying out disc grinding, and finally carrying out cellulase enzymolysis saccharification.

The hot water pretreatment is to add hot water into bamboo wood, and keep the temperature at 120 ℃ for 75 min.

In the hot water pretreatment, according to the solid-liquid ratio of the absolutely dry bamboo wood to the hot water of 1: 6 g/mL.

The green liquor is prepared by blending green liquor of a paper mill, wherein 135.60g/L of sodium carbonate, 22.13g/L of sodium hydroxide and 25.10g/L of sodium sulfide are contained in the green liquor.

The cooking conditions of the green liquor pretreatment are that the solid-to-liquid ratio of the oven-dried bamboo wood to the cooking liquor is 1: 6 g/mL.

The cooking liquor is a mixed liquor of green liquor and water, wherein the addition amount of the green liquor is 10-20% of the mass of the oven-dried bamboo wood in terms of total alkali, and the balance is water.

The treatment temperature of the green liquor pretreatment is 140-160 ℃, and the heat preservation time is 75 min.

The activity of the cellulase is 128FPU/g, and the dosage of the cellulase is 15-20 FPU/g of oven-dried bamboo.

The enzymolysis and saccharification of the cellulase are carried out under the conditions that the pH is 4.5-5.0, the temperature is 50-60 ℃, and the rotating speed of a water bath shaking table is 150 r/min.

Compared with the prior art, the invention has the beneficial results that:

the bamboo wood is pretreated by combining hot water with a green liquor method, most lignin in the bamboo wood can be removed, the negative influence of the lignin on the enzymolysis efficiency can be reduced, the used green liquor can be directly taken from a papermaking factory, the cost can be saved to a certain extent, and therefore the economic benefit is maximized. The cellulose content of the pretreated bamboo wood is improved, the enzymolysis efficiency of the bamboo wood can be improved to a great extent by combining with the enzymolysis of cellulase, the enzymolysis saccharification yield of the cellulose can reach 96.65 percent, almost complete hydrolysis is achieved, and the problem of fossil energy shortage can be effectively relieved by preparing fuel ethanol.

The bamboo is treated by hot water, so that the disc grinding is easier to carry out, the pretreatment energy consumption can be reduced, and the energy is saved; the content of lignin in the bamboo wood can be greatly reduced by green liquor pretreatment, the compact structures of the lignin and the bamboo wood fiber are broken, the contact reaction of cellulase and cellulose is facilitated, the content of the cellulose is 58.93 percent, the content of hemicellulose is 7.17 percent and the content of lignin is 7.7 percent after the pretreatment is finished, the fermentable sugar obtained by every hundred grams of the bamboo wood after enzymolysis is 56.95 grams, which is about 10 grams higher than the fermentable sugar obtained by every hundred grams of the bamboo wood of the current mainstream, the use amount of the cellulase can be reduced by the combination of hot water and the green liquor pretreatment of the bamboo wood, and the enzymolysis efficiency of the cellulose is improved. The bamboo wood is pretreated by combining hot water with green liquor, and the efficiency is higher than that of pure green liquor treatment.

Detailed Description

The process of the present invention is described in further detail below with reference to examples. Example 1 is a comparative example using only hot water without using green liquor, and examples 2, 3, 4, 5, 6 are examples of enzymatic hydrolysis using the method of the present invention.

The green liquor was prepared by laboratory formulation to simulate the green liquor of a paper mill, and each example was prepared by adding 135.60g of sodium carbonate, 22.13g of sodium hydroxide, and 25.10g of sodium sulfide to 1L of water and dissolving them thoroughly for further use.

Example 1

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that the solid-to-liquid ratio of the absolutely dried bamboo to the hot water is 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the green liquor is prepared in a laboratory according to the pharmaceutical composition of the green liquor of a paper mill, and the process of the pretreatment condition of the green liquor comprises the following steps: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 0 percent of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to 150 ℃, and keeping the temperature for 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 15FPU/g, the pH value is 5.0, the temperature is 50 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the cellulose enzymolysis efficiency of 10.73%.

Example 2

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that according to the solid-to-liquid ratio of the absolutely dried bamboo to the hot water of 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the process of the green liquor pretreatment condition is as follows: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 10% of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to 150 ℃, and keeping the temperature for 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 20FPU/g, the pH value is 5.0, the temperature is 55 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the cellulose enzymolysis efficiency of 75.91%.

Example 3

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that the solid-to-liquid ratio of the absolutely dried bamboo to the hot water is 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the process of the green liquor pretreatment condition is as follows: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 10% of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to 140 ℃, and keeping the temperature for 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 15FPU/g, the pH value is 4.8, the temperature is 50 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the enzymolysis efficiency of the cellulose to be 84.30%.

Example 4

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that the solid-to-liquid ratio of the absolutely dried bamboo to the hot water is 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the process of the green liquor pretreatment condition is as follows: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 20% of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to 150 ℃, and keeping the temperature for 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 20FPU/g, the pH value is 4.5, the temperature is 60 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the cellulose enzymolysis efficiency of 96.65%. Through calculation, 56.95g of fermentable sugar can be obtained per hundred grams of bamboo wood after enzymolysis.

Example 5

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that the solid-to-liquid ratio of the absolutely dried bamboo to the hot water is 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the process of the green liquor pretreatment condition is as follows: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 20% of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to ensure that the pretreatment temperature is 160 ℃, and keeping the temperature for 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 20FPU/g, the pH value is 4.5, the temperature is 60 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the cellulose enzymolysis efficiency of 83.75%.

Example 6

(1) Hot water pretreatment:

the hot water pretreatment process comprises the following steps: taking 80g of air-dried bamboo, adding hot water into the bamboo raw material, wherein the adding amount is that the solid-to-liquid ratio of the absolutely dried bamboo to the hot water is 1: 6g/mL of the mixture is pretreated, the pretreatment temperature is 120 ℃, and the heat preservation time is 75 min;

(2) green liquor pretreatment:

taking the bamboo wood prepared in the step (1), and carrying out green liquor pretreatment; the process of the green liquor pretreatment condition is as follows: taking the bamboo wood prepared in the step 1 for green liquor pretreatment, wherein the addition amount of the green liquor is 10% of the mass of the absolutely dry bamboo wood in terms of the total alkali amount, and adding water until the solid-to-liquid ratio of the absolutely dry bamboo wood to the cooking liquor is 1: 6g/mL, heating to ensure that the pretreatment temperature is 150 ℃ and the heat preservation time is 75 min;

(3) disc grinding:

grinding the bamboo wood by using a high-concentration continuous pulping machine, wherein the grinding intervals of three sections of disc mills are 0.2mm, 0.15mm and 0.1mm in sequence, and the ground bamboo wood is used as an experimental material for later use;

(4) enzymolysis of cellulase:

and (3) performing enzymolysis on the raw material prepared in the step (3) by using cellulase, wherein the cellulase treatment process comprises the following steps: and (3) carrying out enzymolysis on 1g of the oven-dried raw material prepared in the step (3) by using cellulase, wherein the activity of the cellulase is 128FPU/g, the dosage of the cellulase is 15FPU/g, the pH value is 4.8, the temperature is 50 ℃, the rotating speed of a shaking table is 150r/min, and the enzymolysis time is 48 h.

Enzymolysis efficiency:

and (4) performing concentration detection on the enzymolysis liquid obtained in the step (4) by using a high performance liquid chromatography, and calculating to obtain the cellulose enzymolysis efficiency of 80.63%.