Method for preparing cellulose hydrolysate by using lignocellulose as raw material
阅读说明：本技术 一种以木质纤维素为原料制备纤维素水解液的方法 (Method for preparing cellulose hydrolysate by using lignocellulose as raw material ) 是由 龚春晓 于 2020-06-28 设计创作，主要内容包括：本发明属于生物质处理技术领域,具体涉及一种以木质纤维素为原料制备纤维素水解液的方法。该方法以木质纤维素为原料,经粉碎后,与表面活性剂混合均匀进行压缩成型,制成木质纤维素产品。制成的木质纤维素产品,经预处理后,加入纤维素酶进行酶解糖化反应。本发明通过在木质纤维素压缩成型过程中添加的表面活性剂,显著降低压缩成型过程中的能量消耗和摩擦,降低木质纤维素压缩设备的零部件磨损；同时,在压缩成型过程中添加的表面活性剂,在后续的以木质纤维素压缩产品为原料的预处理、酶解糖化反应中,起显著促进作用。表面活性剂可以通过改变木质素的表面特性、降低木质素对纤维素酶在酶解过程中的无效吸附,提高酶解糖化效率。(The invention belongs to the technical field of biomass treatment, and particularly relates to a method for preparing cellulose hydrolysate by taking lignocellulose as a raw material. The method takes lignocellulose as raw material, and the lignocellulose is crushed and then evenly mixed with a surfactant for compression molding to prepare the lignocellulose product. The prepared lignocellulose product is pretreated and then added with cellulase for enzymolysis saccharification reaction. According to the invention, the surfactant is added in the lignocellulose compression molding process, so that the energy consumption and friction in the compression molding process are obviously reduced, and the abrasion of parts of lignocellulose compression equipment is reduced; meanwhile, the surfactant added in the compression molding process plays a significant role in the subsequent pretreatment and enzymolysis saccharification reaction taking the lignocellulose compressed product as the raw material. The surfactant can improve the enzymolysis saccharification efficiency by changing the surface characteristics of lignin and reducing the ineffective adsorption of the lignin to cellulase in the enzymolysis process.)
1. A method for preparing cellulose hydrolysate by taking lignocellulose as a raw material is characterized by comprising the following steps:
(1) smashing the lignocellulose raw material to a size smaller than 5cm, and adjusting the water content of the lignocellulose raw material to 8-20%;
(2) adding a surfactant into the lignocellulose raw material, wherein the addition amount of the surfactant is 0.5-5% of the dry weight of the lignocellulose raw material, and uniformly mixing to obtain a mixture;
(3) compressing and molding the mixture obtained in the step (2) to obtain a lignocellulose product, wherein the density of the lignocellulose product is 750-1300 Kg/m3；
(4) Pretreating the lignocellulose product obtained in the step (3) by using dilute acid, water or alkali solution, wherein the mass ratio of the lignocellulose product to the pretreatment solution is as follows: the lignocellulose product is prepared by (2-20) pretreating a solution, wherein the pretreatment temperature is 90-200 ℃, the treatment time is 0.2-5 hours, and the mass percentage concentration of a dilute acid or an alkali solution used for pretreatment is 0.1-5%;
(5) adjusting the pH value of the mixed solution pretreated in the step (4) to 6-8, and then carrying out solid-liquid separation to obtain a solid;
(6) and (3) adding a citric acid-sodium citrate buffer solution with the pH value of 4.5-5.5 and the molar concentration of 0.1M into the solid obtained in the step (5), adding cellulase, and performing an enzymatic saccharification reaction, wherein the initial mass concentration of the solid is 5-30% during the enzymatic saccharification reaction, the addition amount of the cellulase is 10-50 FPU/g of the solid, the reaction is performed for 24-72 hours at the temperature of 45-50 ℃ and the oscillation speed of 140-160 r/min during the enzymatic saccharification reaction, and the solid-liquid separation is performed on the reactant after the enzymatic hydrolysis reaction to obtain the cellulose hydrolysate.
2. The method according to claim 1, wherein the surfactant in step (2) is polyethylene glycol, and the molecular weight of the polyethylene glycol is 1000 to 8000.
3. The method of claim 1, wherein the dilute acid used in step (4) is one or more of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, or dilute phosphoric acid, mixed in any proportion.
4. The method of claim 1, wherein the alkaline solution used in step (4) is one or more of sodium hydroxide, potassium hydroxide, calcium oxide or ammonia water mixed in any proportion.
Technical Field
The invention belongs to the technical field of biomass treatment, and particularly relates to a method for preparing cellulose hydrolysate by taking lignocellulose as a raw material.
Background
With the gradual depletion of fossil fuels and the growing environmental concerns, the research and utilization of renewable energy sources has been a key area of global attention. The bioethanol is an important research object for biomass energy utilization due to the characteristics of renewability, environmental friendliness and the like. Lignocellulose biomass is used as a raw material, and can be converted into bioethanol after pretreatment, enzymolysis saccharification and fermentation. However, lignocellulosic biomass such as crop straw, and forest waste such as branches and wood chips, due to its loose structure and low density, causes many problems for storage, transportation and subsequent utilization.
The biomass compression molding can well solve the problems of low density, difficult storage and utilization and the like of the lignocellulose biomass. The product after compression molding has the characteristics of uniform shape and characteristics, higher energy density and the like, and meanwhile, the transportation cost and the storage space can be reduced, and the subsequent application is facilitated. At present, biomass compression equipment for industrial application mainly comprises: a ring die (flat die) granulator (ring/flat die pellet mill), a ring die briquette mill (ring die briquette mill), a spiral briquetting machine (screw extruder), a piston type briquetting machine (piston press), etc., wherein the ring die granulator and the ring die briquetting machine are compression equipment which are widely applied industrially at present. However, biomass compression equipment has problems of high energy consumption, rapid wear of parts, low productivity, and the like. Taking a ring die granulator as an example, the ring die is a core component of the granulator, the working performance and the service life of the ring die directly influence the quality of product particles and the production cost, and the friction generated in the granulating process can cause the abrasion and deformation of the ring die of the granulator, so that the service life of the granulator is reduced, and the development of a biomass compression molding technology is restricted.
Lignocellulose biomass can be converted into bioethanol after pretreatment, enzymolysis saccharification and fermentation, and a surfactant is added in the pretreatment process, so that the method is an effective method for improving the subsequent enzymolysis saccharification efficiency. The surfactant can improve the enzymolysis saccharification efficiency by changing the surface characteristics of lignin and reducing the ineffective adsorption of the lignin to cellulase in the enzymolysis process.
Disclosure of Invention
The invention aims to provide a method for preparing cellulose hydrolysate by taking lignocellulose as a raw material, and provides a novel cellulose hydrolysis process to reduce energy consumption and improve enzymolysis saccharification efficiency.
The invention provides a method for preparing cellulose hydrolysate by taking lignocellulose as a raw material, which comprises the following steps:
(1) smashing the lignocellulose raw material to a size smaller than 5cm, and adjusting the water content of the lignocellulose raw material to 8-20%;
(2) adding a surfactant into the lignocellulose raw material, wherein the addition amount of the surfactant is 0.5-5% of the dry weight of the lignocellulose raw material, and uniformly mixing to obtain a mixture;
(3) compressing and molding the mixture obtained in the step (2) to obtain a lignocellulose product, wherein the density of the lignocellulose product is 750-1300 Kg/m3；
(4) Pretreating the lignocellulose product obtained in the step (3) by using dilute acid, water or alkali solution, wherein the mass ratio of the lignocellulose product to the pretreatment solution is as follows: the lignocellulose product is prepared by (2-20) pretreating a solution, wherein the pretreatment temperature is 90-200 ℃, the treatment time is 0.2-5 hours, and the mass percentage concentration of a dilute acid or an alkali solution used for pretreatment is 0.1-5%;
(5) adjusting the pH value of the mixed solution pretreated in the step (4) to 6-8, and then carrying out solid-liquid separation to obtain a solid;
(6) and (3) adding the solid obtained in the step (5) into a citric acid-sodium citrate buffer solution with the pH value of 4.5-5.5 and the molar concentration of 0.1M, adding cellulase, and performing an enzymatic saccharification reaction, wherein the initial mass concentration of the solid is 5-30% during the enzymatic saccharification reaction, the addition amount of the cellulase is 10-50 FPU/g of the solid, the reaction is performed for 24-72 hours at the temperature of 45-50 ℃ and the oscillation speed of 140-160 r/min during the enzymatic saccharification reaction, and the solid-liquid separation is performed on the reactant after the enzymatic saccharification reaction to obtain the cellulose hydrolysate.
The surfactant in the method is polyethylene glycol (PEG), and the molecular weight of the polyethylene glycol is 1000-8000.
The diluted acid used in the method is one or more of diluted sulfuric acid, diluted hydrochloric acid, diluted nitric acid or diluted phosphoric acid which are mixed in any proportion. The alkaline solution is one or more of sodium hydroxide, potassium hydroxide, calcium oxide or ammonia water mixed in any proportion.
The method for preparing the cellulose hydrolysate by taking the lignocellulose as the raw material has the advantages that:
the method for preparing the cellulose hydrolysate by taking the lignocellulose as the raw material compresses and molds the loose lignocellulose raw material into the high-density lignocellulose product, the energy density of the lignocellulose can be increased after compression molding treatment, the collection and transportation cost and the storage space are reduced, and the compressed lignocellulose product has more uniform and stable properties and is beneficial to subsequent application. The surfactant added in the method in the lignocellulose compression molding process can play a role in lubrication in the compression molding process, so that the energy consumption and friction in the compression process are reduced, the abrasion of compression equipment is reduced, the service life of the equipment is prolonged, and the compression efficiency is improved. In addition, the surfactant added in the compression molding process plays a significant role in the subsequent pretreatment and enzymolysis saccharification reaction taking the lignocellulose compressed product as the raw material. The surfactant can improve the enzymolysis saccharification efficiency by changing the surface characteristics of lignin and reducing the ineffective adsorption of the lignin to cellulase in the enzymolysis process.
Drawings
FIG. 1 is a process flow diagram of the process of the present invention.
Detailed Description
The method for preparing the cellulose hydrolysate by using the lignocellulose as the raw material, which is provided by the invention, has the process flow chart shown in figure 1 and comprises the following steps:
(1) smashing the lignocellulose raw material to a size smaller than 5cm, and adjusting the water content of the lignocellulose raw material to 8-20%;
(2) adding a surfactant into the lignocellulose raw material, wherein the addition amount of the surfactant is 0.5-5% of the dry weight of the lignocellulose raw material, and uniformly mixing to obtain a mixture;
(3) compressing and molding the mixture obtained in the step (2) to obtain a lignocellulose product, wherein the density of the lignocellulose product is 750-1300 Kg/m3(ii) a The apparatus for compression molding the mixture in the method of the present invention includes, but is not limited to: ring die granulator (flat die), ring die briquetting machine (ring die briquetting mill), and screw type briquetting machineMachines (screen extruders), piston presses (piston presses) or single-barrel closed compression units (single press units);
(4) pretreating the lignocellulose product obtained in the step (3) by using dilute acid, water or alkali solution, wherein the mass ratio of the lignocellulose product to the pretreatment solution is as follows: the lignocellulose product is prepared by (2-20) pretreating a solution, wherein the pretreatment temperature is 90-200 ℃, the treatment time is 0.2-5 hours, and the mass percentage concentration of a dilute acid or an alkali solution used for pretreatment is 0.1-5%;
(5) adjusting the pH value of the mixed solution pretreated in the step (4) to 6-8, and then carrying out solid-liquid separation to obtain a solid;
(6) and (3) adding a citric acid-sodium citrate buffer solution with the pH value of 4.5-5.5 and the molar concentration of 0.1M into the solid obtained in the step (5), adding cellulase, and performing an enzymatic saccharification reaction, wherein the initial mass concentration of the solid is 5-30% during the enzymatic saccharification reaction, the addition amount of the cellulase is 10-50 FPU/g of the solid, the reaction is performed for 24-72 hours at the temperature of 45-50 ℃ and the oscillation speed of 140-160 r/min during the enzymatic saccharification reaction, and the solid-liquid separation is performed on the reactant after the enzymatic hydrolysis reaction to obtain the cellulose hydrolysate.
The surfactant in the method is polyethylene glycol (PEG), and the molecular weight of the polyethylene glycol can be 1000-8000.
The diluted acid used in the method is one or more of diluted sulfuric acid, diluted hydrochloric acid, diluted nitric acid or diluted phosphoric acid which are mixed in any proportion. The alkaline solution is one or more of sodium hydroxide, potassium hydroxide, calcium oxide or ammonia water mixed in any proportion.
The present invention will be described in further detail with reference to the following specific examples and drawings, but the examples are not intended to limit the invention in any manner.