Novel method for saccharification of ligno-cellulose

Abstract

The invention relates to a new method for processing lignocellulose by saccharification, comprising dilute acid pretreatment, milling and crushing, cellulase compounding and enzymolysis saccharification process. The detail method thereof comprises the following steps: the crushed lignocellulose raw materials are pretreated with dilute acid with the H <+> concentration of 0.01mol/L-0.1mol/L and later milled and crushed, and then acidolysis sugar solution is obtained; at least two types of cellulase are mixed with xylanase for obtaining compound cellulase, and then further enzymolysis saccharification treatment is carried out to the rest solid after enzymolysis and milling for obtaining enzymolysis sugar solution. By using the process that the milling of dilute acid is combined with the one-step enzymolysis of compound enzyme, the hydrolysis sugar yield of the lignocellulose raw materials can be up to more than 90 percent. The method has the advantages of mild reaction condition, simple operation, and high enzymolysis efficiency; moreover, the obtained sugar solution after being processed produces no inhibition to the follow-up fermentation, can be comprehensively utilized, and causes no environmental pollution, etc.

Description

Technical field [0001] The invention relates to a new method for saccharification and treatment of lignocellulose, in particular to a method for improving cellulase-catalyzed lignocellulose saccharification by dilute acid ball milling and cellulase compounding, and belongs to the technical field of biochemical industry. Background technique [0002] Ethanol is a promising fuel to replace limited petroleum. Currently, the main raw material of fuel ethanol is grain, but the output of grain production ethanol is limited. It is the cellulosic material that can really convert a large amount of ethanol. The challenge of converting cellulosic materials to ethanol is low yield and high cost. The pretreatment of cellulosic materials is a key step in the process of converting ethanol. The optimization of this step can significantly increase the hydrolysis rate of cellulose, thereby reducing the production cost of ethanol. [0003] In the process of using lignocellulose to produce ethanol, ...

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Problems solved by technology

[0005] Chinese patent CN1806945 discloses a method of using straw pretreatment and enzymatic hydrolysis process to completely enzymatically hydrolyze straw cellulose. The straw is first subjected to steam explosion treatment, and then washed with hot water to remove hemicellulose polysaccharides. After drying, it is mixed with ionic liquid Mixing, microwave heating or direct heating, and then repeatedly rinse the treated straw with water, the solvent in the washing liquid can be recovered by distillation and other methods, and rinse the treated straw with cellulose in a pH4.8 buffer solution at 50 °C After 48-72 hours of enzymatic hydrolysis, the enzymatic hydrolysis rate of cellulose can reach 100%, but the above-mentioned defects of steam explosion treatment still exist, and heating is still required after steam explosion, which consumes a lot of energy, the production cost is too high, and the process is cumbersome ; U.S. Patent No. 5,562,777 discloses a method for hydrolyzing cellulose and hemicellulose with a strong acid. The mixture of concentrated sulfuric acid and cellulose and hemicellulose with a concentration of 70% to 77% is mixed uniformly at a ratio of 1.25:1 to form a gel , then add water to dilute the concentration of sulfuric acid in the gel to 20% to 30%, then heat to 80°C to 100°C, and treat for 40min to 480min. This process effectively destroys the crystal structure of cellulose, which is beneficial to improve the subsequent processing cellulose degradation rate, but this process also has the disadvantages of high processing temperature, large amount of strong acid, and high production cost; Chinese patent CN1970781 discloses a method for ultrasonically modified cellulase to catalyze lignocellulose saccharification, through pulverization (20 purpose) and alkali treatment (normal temperature, 3% to 8%) to separate the lignin from the raw material, and use activated monomethoxypolyethylene glycol to react with cellulase in citric acid-sodium citrate buffer solution to obtain improved β-glucosidase, amylase and pectinase are mixed to obtain a compound enzyme liquid, and the compound enzyme is added to the pretreated raw material according to the corresponding proportion, and the ultrasonic wave ( 80W~300W) for enzyme-catalyzed reaction, and finally filtered and evaporated under reduced pressure to obtain concentrated sugar solution (25%~35%). This method adopts the method of enzyme modification and compounding to improve the conversion rate of cellulose However, the concentration of lye in this method is too high, which has caused great pressure on the maintenance of production equipment and production costs. Due to the poor effect of alkali treatment in the early stage, the enzymatic hydrolysis process in the

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