Application method of surfactant (Tween)

Abstract

The invention relates to an application method of a surfactant (Tween), in particular to a method for improving holocellulose enzymolysis efficiency by using the surfactant (Tween), which comprises the following steps: S1, mixing the surfactant with a mixed solution containing holocellulose to obtain an enzymolysis system, the surfactant being selected from Tween and / or glycerol; s2, adding enzyme liquid into an enzymolysis system, and performing enzymolysis on holocellulose in the presence of an enzymolysis accelerant and enzyme. According to the method provided by the invention, the surfactants Tween and / or glycerol are / is added into the holocellulose enzymolysis system with high solid concentration, so that invalid adsorption of cellulase in the enzymolysis process can be effectively reduced, and the enzymolysis efficiency of holocellulose is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cellulose enzymatic saccharification, and in particular to an application method of a surfactant (Tween), and in particular to a method for improving the enzymatic hydrolysis efficiency of holocellulose by utilizing the surfactant (Tween). Background Art

[0002] With the rapid development of society, the consumption of fossil fuels is increasing. Due to the non-renewable nature of fossil fuels, finding alternative energy sources has become the focus of attention. The use of lignocellulosic biomass such as corn stalks, corn cobs, rice stalks and other crop stalks, sawdust, branches and other agricultural and forestry wastes to prepare cellulosic ethanol is called "second-generation fuel ethanol". It is of great significance in increasing the added value of agricultural and forestry wastes, reducing environmental pollution, and promoting rural economic development.

[0003] The mainstream technologies for the preparation of cellulosic ethanol include pretreatment, enzymatic hydrolysis and fermentation. Among them, the efficient acquisition of sugar products from lignocellulosic biomass is the most critical technical difficulty in the cellulosic ethanol process. The acquisition of sugar products mainly comes from pretreatment and enzymatic hydrolysis. However, the cost of cellulase used in enzymatic hydrolysis is relatively high, and the concentration of sugar products generated is low, resulting in low enzymatic hydrolysis efficiency. Enzymatic hydrolysis with high-concentration raw materials is a very effective method to increase the concentration of output sugar products, but when the concentration of pretreated lignocellulosic solid raw materials is high, it will inevitably bring about problems of high viscosity and uneven mixing, which will also inhibit the smooth progress of enzymatic hydrolysis. Summary of the invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention provides a method for improving the enzymatic hydrolysis efficiency of holocellulose, especially holocellulose at high solid concentration. The method provided by the present invention can effectively reduce the ineffective adsorption of cellulase during the enzymatic hydrolysis process and improve the enzymatic hydrolysis efficiency of holocellulose by adding Tween and / or glycerol to the high solid concentration holocellulose enzymatic hydrolysis system.

[0005] The method for improving the enzymatic hydrolysis efficiency of holocellulose provided by the present invention comprises the following steps:

[0006] S1: mixing a surfactant with a mixed solution containing holocellulose to obtain an enzymatic hydrolysis system, wherein the surfactant is selected from Tween and / or glycerol;

[0007] S2: adding enzyme solution into the enzymatic hydrolysis system to hydrolyze the holocellulose in the presence of surfactant and enzyme.

[0008] In some embodiments, based on the mass of the enzymatic hydrolysis system, the mass content of the holocellulose is 10% to 20%, for example, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or any value therebetween.

[0009] In some embodiments, based on the mass of the enzymatic hydrolysis system, the mass content of the surfactant is 0.1%-1.5%. In some embodiments, the mass content of the surfactant is 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4% or any value therebetween. In some embodiments, the mass content of the surfactant is 0.5%-1.0%. When the concentration of the surfactant is too low, the lifting effect is not obvious, and when it is too high, the lifting effect increases and remains basically unchanged.

[0010] In some embodiments, the Tween is selected from one or more of Tween 20, Tween 40, Tween 60 and Tween 80.

[0011] In some embodiments, the surfactant is Tween 80 and glycerol.

[0012] In some embodiments, the mass ratio of Tween 80 to glycerol is 1:(0.1-10), for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2, 1:2.1, 1:2.3, 1:2.5, 1:2.7, 1:2.9, 1:3, 1:3.1, 1:3. 3, 1:3.5, 1:3.7, 1:3.9, 1:4, 1:4.1, 1:4.3, 1:4.5, 1:4.7, 1:4.9, 1:5, 1:5.1, 1:5.3, 1:5.5, 1:5.7, 1:5.9, 1:6, 1:6.1, 1:6.3, 1:6.5, 1:6.7, 1:6.9, 1:7, 1:7.1, 1:7.3, 1:7.5, 1:7.7, 1:7.9, 1:8, 1:9 or any value therebetween. When Tween and glycerol are added to the enzymatic hydrolysis system in a certain ratio, the two have a synergistic effect.

[0013] In some embodiments, the raw material for preparing the holocellulose is selected from wheat straw.

[0014] In some embodiments, the method for preparing holocellulose includes crushing the raw material for preparing holocellulose, mixing the crushed raw material with alkali solution and then performing heat treatment, and washing and drying the heat-treated material to obtain the holocellulose.

[0015] In some embodiments, the particle size of the crushed raw material is 20 mesh-40 mesh.

[0016] In some embodiments, the alkali solution is selected from sodium hydroxide solution. In some embodiments, the concentration of the sodium hydroxide solution is 2%-6%, for example, 3%, 4% or 5%.

[0017] In some embodiments, the mass ratio of the alkali solution to the mass of the crushed raw material is (2.5-3):1.

[0018] In some embodiments, the temperature of the heat treatment is 95° C.-110° C. In some embodiments, the time of the heat treatment is 2 h-4 h, such as 2.5 h-3.5 h.

[0019] In some embodiments, the enzyme solution includes a cellulase solution, a cellobiase solution, and a xylanase solution.

[0020] In some embodiments, based on the dry basis mass of holocellulose, the added amount of the cellulase solution is 10wt%-35wt%, for example, 13wt%, 15wt%, 17wt%, 20wt%, 23wt%, 25wt%, 27wt%, 30wt% or 33wt%.

[0021] In some embodiments, based on the dry basis weight of holocellulose, the added amount of the cellobiase solution is 40 wt%-60 wt%, for example, 43 wt%, 45 wt%, 47 wt%, 50 wt%, 53 wt%, 55 wt% or 57 wt%.

[0022] In some embodiments, based on the dry weight of holocellulose, the amount of the xylanase solution added is 5 wt%-15 wt%, for example, 6 wt%, 8 wt%, 10 wt%, 12 wt% or 14 wt%.

[0023] In some embodiments, the filter paper enzyme activity of the cellulase is 100-300 IU / g, for example, 150 IU / g, 200 IU / g or 250 IU / g.

[0024] In some embodiments, the standard enzyme activity of the cellobiase is 100-400 IU / g, such as 150 IU / g, 200 IU / g, 250 IU / g, 300 IU / g or 350 IU / g.

[0025] In some embodiments, the enzymatic activity of the xylanase is 800-1200 IU / g, for example, 850 IU / g, 900 IU / g, 950 IU / g, 1000 IU / g, 1050 IU / g, 1100 IU / g or 1150 IU / g.

[0026] In some embodiments, the pH value of the enzymatic hydrolysis system is 4.5-5.5. In some embodiments, sulfuric acid and sodium hydroxide solution are used to adjust the pH value of the enzymatic hydrolysis system.

[0027] In some embodiments, the enzymolysis temperature is 45° C.-52° C., for example, 46° C., 47° C., 48° C., 49° C., 50° C. or 51° C. In some embodiments, the enzymolysis time is 72 h-96 h, for example, 76 h, 80 h, 84 h, 88 h or 92 h.

[0028] In some embodiments, the enzymolysis is performed in a shaker. In some embodiments, the shaker speed is 150 rpm-230 rpm.

[0029] In some embodiments, the method for improving the enzymatic hydrolysis efficiency of holocellulose provided by the present invention comprises the following specific steps:

[0030] The raw material for preparing holocellulose, such as wheat straw, is crushed and then steamed with alkali, then washed with water until the pH value is 7-8, and dried to obtain wheat straw holocellulose;

[0031] The holocellulose is mixed with a surfactant, Tween, and / or glycerol to obtain a high-solid enzymatic hydrolysis system;

[0032] Then, cellulase solution, cellobiase solution and xylanase solution are added into the system for enzymolysis.

[0033] The beneficial effects of the present invention are:

[0034] (1) Adding Tween and / or glycerol to the high solid concentration enzymatic hydrolysis system can increase the fluidity of the enzymatic hydrolysis system, which is conducive to the full contact reaction between the enzyme protein molecules and holocellulose.

[0035] (2) Tween and / or glycerol can bind to part of the lignin in the holocellulose, thereby reducing the irreversible binding of lignin and cellulase, alleviating enzyme poisoning, improving enzyme utilization and enzymatic efficiency, and reducing costs. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention.

[0037] The enzymatic hydrolysis efficiency described in the present invention is expressed by the hydrolysis rate of wheat straw holocellulose, and the specific calculation formula is:

[0038] Wheat straw holocellulose enzymatic hydrolysis rate (%) = total reducing sugar content (g) / wheat straw holocellulose reducing sugar content (g) × 100%; where,

[0039] The total reducing sugar content is: the total reducing sugar mass in the enzymatic hydrolysis system after enzymatic hydrolysis is completed;

[0040] The reducing sugar content of wheat straw holocellulose is: the sum of the mass of cellulose converted into glucose and the mass of hemicellulose converted into xylose in wheat straw holocellulose;

[0041] The enzymatic hydrolysis system consists of wheat straw holocellulose substrate and mixed enzyme solution.

[0042] The particle size of the wheat straw after crushing is preferably 20-40 mesh. The alkali solution used in alkali cooking is preferably a sodium hydroxide solution with a concentration of 2wt%-6wt%, and the amount used is 2.5-3 times the mass of the straw powder. The cooking temperature is preferably 95°C-110°C, and the cooking time is preferably 2.5h-3.5h. After cooking, wash with pure water to pH7-8 and dry at a constant temperature of 90°C. The following examples and comparative examples all use this method to pretreat wheat straw.

[0043] Embodiment 1

[0044] (1) Preparation of surfactant aqueous solutions: Prepare 10 wt % concentration of Tween-20, Tween-40, Tween-60, Tween-80, and glycerol aqueous solutions, numbered as A1, B1, C1, D1, and E1, respectively.

[0045] (2) Preparation of high-solid enzymatic hydrolysis system: Wheat holocellulose was taken and the dry basis content was determined to be 95 wt%. The mixture was divided into 5 portions, each of which was 31.58 g (i.e., 30 g in dry weight). 100 g of pure water was added and mixed. Then, 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Then, 30 mL of A1, B1, C1, D1, and E1 solutions were added respectively. Pure water was added to make the volume to 300 mL to prepare a high-solid enzymatic hydrolysis system containing 10 wt% wheat holocellulose and 1 wt% of each surfactant. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0046] (3) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at 50°C and 200 rpm, and the pH of the enzymatic hydrolysis system was controlled at 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution, and the enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 1 below.

[0047] Comparative Example 1

[0048] (1) Preparation of a high-solid enzymatic hydrolysis system: wheat holocellulose was taken and the dry basis content was determined to be 95 wt %. 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Pure water was added to make the volume to 300 mL to prepare a high-solid enzymatic hydrolysis system containing 10 wt % wheat holocellulose. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0049] (2) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at 50°C and 200 rpm, and the pH of the enzymatic hydrolysis system was controlled to 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution, and the enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 1 below.

[0050] In Table 1, the enzymatic hydrolysis efficiency improvement rate = (enzymatic hydrolysis efficiency of Example 1 - enzymatic hydrolysis efficiency of Comparative Example 1) / enzymatic hydrolysis efficiency of Comparative Example 1 × 100%.

[0051] Table 1

[0052]

[0053] From the data in Table 1, it can be seen that when Tween or glycerol is added to the wheat straw holocellulose enzymatic hydrolysis system at a concentration of 10wt%, the ineffective adsorption of lignin on cellulase during the enzymatic hydrolysis process can be effectively reduced, thereby improving the enzymatic hydrolysis efficiency of wheat straw holocellulose, with the highest improvement rate reaching 12.5%.

[0054] Embodiment 2

[0055] (1) Preparation of surfactant aqueous solutions: Prepare 10 wt % concentration of Tween-20, Tween-40, Tween-60, Tween-80, and glycerol aqueous solutions, numbered as A2, B2, C2, D2, and E2, respectively.

[0056] (2) Preparation of a high-solid enzymatic hydrolysis system: Wheat holocellulose was taken and the dry basis content was determined to be 95 wt%. The mixture was divided into 5 portions, each of which was 31.58 g (i.e., 30 g in dry weight). 100 g of pure water was added and mixed. Then, 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Then, 20 mL of each of A2, B2, C2, D2, and E2 solutions were added respectively. Pure water was then added to make the volume to 200 mL to prepare a high-solid enzymatic hydrolysis system containing 15 wt% wheat holocellulose and 1 wt% of each surfactant. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL of sulfuric acid solution and 0.1 mol / mL of sodium hydroxide solution.

[0057] (3) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at a temperature of 50° C. and a rotation speed of 200 rpm. The pH of the enzymatic hydrolysis system was controlled at 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution. The enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 2 below.

[0058] Comparative Example 2

[0059] (1) Preparation of high-solid enzymatic hydrolysis system: wheat holocellulose was taken and the dry basis content was determined to be 95 wt %. 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Pure water was added to make the volume to 200 mL to prepare a high-solid enzymatic hydrolysis system containing 15 wt % wheat holocellulose. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0060] (2) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at 50°C and 200 rpm, and the pH of the enzymatic hydrolysis system was controlled to 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution, and the enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 2 below.

[0061] In Table 2, the enzymatic hydrolysis efficiency improvement rate = (enzymatic hydrolysis efficiency of Example 2 - enzymatic hydrolysis efficiency of Comparative Example 2) / enzymatic hydrolysis efficiency of Comparative Example 2 × 100%.

[0062] Table 2

[0063]

[0064] From the data in Table 2, it can be seen that when Tween or glycerol is added to the wheat straw holocellulose enzymatic hydrolysis system at a concentration of 15wt%, the ineffective adsorption of lignin on cellulase during the enzymatic hydrolysis process can be effectively reduced, thereby improving the enzymatic hydrolysis efficiency of wheat straw holocellulose, with the highest improvement rate reaching 12.85%.

[0065] Embodiment 3

[0066] (1) Preparation of surfactant aqueous solutions: Prepare 10 wt % concentration of Tween-20, Tween-40, Tween-60, Tween-80, and glycerol aqueous solutions, numbered as A3, B3, C3, D3, and E3 respectively.

[0067] (2) Preparation of high-solid enzymatic hydrolysis system: wheat holocellulose was taken and the dry basis content was determined to be 95 wt%. The mixture was divided into 5 portions, each of which was 31.58 g (i.e., 30 g dry weight). 100 g pure water was added and mixed. Then, 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Then, 15 mL of A2, B2, C2, D2, and E2 solutions were added respectively. Pure water was added to make the volume to 150 mL to prepare a high-solid enzymatic hydrolysis system containing 20 wt% wheat holocellulose and 1 wt% of each surfactant. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0068] (3) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at a temperature of 50° C. and a rotation speed of 200 rpm. The pH of the enzymatic hydrolysis system was controlled at 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution. The enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 3 below.

[0069] Comparative Example 3

[0070] (1) Preparation of high-solid enzymatic hydrolysis system: wheat holocellulose was taken and the dry basis content was determined to be 95 wt %. 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. Pure water was added to make the volume to 150 mL to prepare a high-solid enzymatic hydrolysis system containing 20 wt % wheat holocellulose. The pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0071] (2) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at a temperature of 50°C and a rotation speed of 200 rpm. The pH of the enzymatic hydrolysis system was controlled to 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution. The enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 3 below.

[0072] In Table 3, the enzymolysis efficiency improvement rate = (enzymolysis efficiency of Example 3 - enzymolysis efficiency of Comparative Example 3) / enzymolysis efficiency of Comparative Example 3 × 100%.

[0073] Table 3

[0074]

[0075] From the data in Table 3, it can be seen that when Tween or glycerol is added to the wheat straw holocellulose enzymatic hydrolysis system at a concentration of 20wt%, the ineffective adsorption of lignin on cellulase during the enzymatic hydrolysis process can be effectively reduced, thereby improving the enzymatic hydrolysis efficiency of wheat straw holocellulose, with the highest improvement rate reaching 12.3%.

[0076] Embodiment 4

[0077] (1) Preparation of surfactant aqueous solution: Prepare a 10 wt% Tween-80 aqueous solution.

[0078] (2) Preparation of high-solid enzymatic hydrolysis system: wheat holocellulose was measured to have a dry basis content of 95 wt%, and divided into 6 portions, denoted as A4, B4, C4, D4, E4, and F4, each with 31.58 g (i.e., 30 g dry weight), and 100 g pure water was added to mix well. Then, 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g), and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. 4. Add 2 mL, 4 mL, 8 mL, 12 mL, 16 mL and 20 mL of 10 wt% Tween-80 solution to E4 and F4, respectively, and then add pure water to make the volume to 200 mL, to prepare high-solid enzymatic hydrolysis systems containing 15 wt% wheat holocellulose and 0.1%, 0.2%, 0.4%, 0.6%, 0.8% and 1% Tween-80, respectively, and adjust the pH to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0079] (3) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at a temperature of 50° C. and a rotation speed of 200 rpm. The pH of the enzymatic hydrolysis system was controlled to 4.8-5.0 using a 0.05 mol / mL sulfuric acid solution and a 0.1 mol / mL sodium hydroxide solution. The enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 4 below.

[0080] In Table 4, the enzymolysis efficiency improvement rate = (enzymolysis efficiency of Example 4 - enzymolysis efficiency of Comparative Example 2) / enzymolysis efficiency of Comparative Example 2 × 100%.

[0081] Table 4

[0082]

[0083] Embodiment 5

[0084] (1) Preparation of surfactant aqueous solution: prepare 10 wt % glycerol aqueous solution and 10 wt % Tween-80 aqueous solution.

[0085] (2) Preparation of high-solid enzymatic hydrolysis system: wheat holocellulose was taken and the dry basis content was determined to be 95 wt %. The mixture was divided into three portions, namely A5, B5 and C5, each of which was 31.58 g (i.e., 30 g dry weight). 100 g pure water was added and mixed. Then, 10 mL of cellulase solution (specific enzyme activity of 100 IU / g), 15 mL of cellobiase solution (specific enzyme activity of 200 IU / g) and 3 mL of xylanase solution (specific enzyme activity of 1000 IU / g) were added. 4 mL of 10 wt % glycerol aqueous solution and 16 mL of 10 wt % Tween-80 aqueous solution were added to A5. 10 wt % glycerol aqueous solution was added to B5. 10 ml of oil-water solution and 10 ml of 10 wt% Tween-80 aqueous solution, 16 ml of 10 wt% glycerol aqueous solution and 4 ml of 10 wt% Tween-80 aqueous solution were added to C5, and then pure water was added to make the volume to 200 ml to prepare a high-solid enzymatic hydrolysis system containing 15 wt% wheat holocellulose and 0.2% glycerol and 0.8% Tween-80, 0.5% glycerol and 0.5% Tween-80, 0.8% glycerol and 0.2% Tween-80, and the pH was adjusted to 4.5-5.5 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution.

[0086] (3) Enzymatic hydrolysis reaction: The enzymatic hydrolysis system was placed in a water bath shaker at 50°C and 200 rpm, and the pH of the enzymatic hydrolysis system was controlled at 4.8-5.0 using 0.05 mol / mL sulfuric acid solution and 0.1 mol / mL sodium hydroxide solution, and the enzymatic hydrolysis was performed for 96 hours. The specific enzymatic hydrolysis efficiency after the enzymatic hydrolysis was completed is shown in Table 5 below.

[0087] In Table 5, the enzymolysis efficiency improvement rate = (enzymolysis efficiency of Example 5 - enzymolysis efficiency of Comparative Example 2) / enzymolysis efficiency of Comparative Example 2 × 100%.

[0088] Table 5

[0089]

[0090] From the data in Table 5, it can be seen that when Tween and glycerol are added to the wheat straw holocellulose enzymatic hydrolysis system in a certain ratio, the enzymatic hydrolysis efficiency of wheat straw holocellulose can be improved by 14.53%, and the two have a synergistic effect.

[0091] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for applying a surfactant (Tween), comprising the following steps: S1: mixing a surfactant with a mixed solution containing holocellulose to obtain an enzymatic hydrolysis system, wherein the surfactant is selected from Tween and / or glycerol; S2: adding enzyme solution into the enzymatic hydrolysis system to hydrolyze the holocellulose in the presence of surfactant and enzyme.

2. The method according to claim 1, characterized in that Based on the mass of the enzymatic hydrolysis system, the mass content of the holocellulose is 10% to 20%.

3. The method according to claim 1 or 2, characterized in that: Based on the mass of the enzymatic hydrolysis system, the mass content of the surfactant is 0.1%-1.5%, preferably 0.5%-1.0%.

4. The method according to any one of claims 1 to 3, characterized in that The Tween is selected from one or more of Tween 20, Tween 40, Tween 60 and Tween 80; Preferably, the surfactant is selected from Tween 80 and glycerol, and more preferably, the mass ratio of Tween 80 to glycerol is 1:(0.1-10).

5. The method according to any one of claims 1 to 4, characterized in that The raw material for preparing the holocellulose is selected from wheat straw.

6. The method according to any one of claims 1 to 5, characterized in that The method for preparing holocellulose comprises crushing the raw material for preparing holocellulose, mixing the crushed raw material with alkali solution and then performing heat treatment, and washing and drying the heat-treated material to obtain the holocellulose.

7. The method according to claim 6, characterized in that The particle size of the crushed raw material is 20 mesh to 40 mesh; and / or The alkali solution is selected from sodium hydroxide solution, and preferably the concentration of the sodium hydroxide solution is 2%-6%; and / or The mass ratio of the alkali solution to the crushed raw material is (2.5-3):1; and / or The heat treatment temperature is 95°C-110°C, and the time is 2h-4h.

8. The method according to any one of claims 1 to 7, characterized in that The enzyme solution includes cellulase solution, cellobiase solution and xylanase solution, Preferably, based on the dry basis weight of holocellulose, the amount of the cellulase solution added is 10wt%-35wt%, the amount of the cellobiase solution added is 40wt%-60wt%, and the amount of the xylanase solution added is 5wt%-15wt%; Preferably, the filter paper enzyme activity of the cellulase is 100-300 IU / g, the standard enzyme activity of the cellobiase is 100-400 IU / g, and the enzyme activity of the xylanase is 800-1200 IU / g.

9. The method according to any one of claims 1 to 8, characterized in that The pH value of the enzymatic hydrolysis system is 4.5-5.

5.

10. The method according to any one of claims 1 to 9, characterized in that The enzymolysis temperature is 45°C-52°C, and the enzymolysis time is 72h-96h; and / or The enzymatic hydrolysis is carried out in a shaker, and preferably the shaking speed is 150 rpm-230 rpm.

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