Process for preparing multicomponent liquid glucose and lignose while effectively hydrolyzing lignocellulosic biomass

Abstract

The invention discloses a method for efficiently hydrolyzing lignocellulosic biomass and synchronously preparing multi-component liquid glucose and lignin. The method comprises the steps that: the lignocellulosic biomass through physical crushing is added with phosphoric acid to perform acid hydrolysis; then organic solvent is added to extract the lignin, the layering and the phase separation are performed, then the lignin is extracted out while the organic solvent is reclaimed under the condition of pressure reduction and distillation; phosphoric acid can be reclaimed through steps such as neutralization, filtration, acidification and so on, hemicellulose hydrolyzed liquid glucose is obtained at the same time; and the remained cellulose undergoes the zymohydrolysis to prepare cellulosic hydrolyzed liquid glucose. The method can separate lignin, hemicellulose and cellulose, remarkably decreases the degree of crystallinity of the cellulose hydrolyzed by phosphoric acid, and remarkably improves the zymohydrolysis efficiency; and the prepared hydrolyzed liquid glucose does not contain fermentation inhibitors. The method has mild treatment conditions, simple process and less side reactions; the phosphoric acid and the organic solvent can both be reclaimed and circularly used; and the method is environment-friendly, and has broad social and economic benefits.

Description

technical field [0001] The invention belongs to the technical field of bioengineering, and relates to a method for efficiently hydrolyzing lignocellulosic biomass, which can simultaneously obtain cellulose hydrolyzate, hemicellulose hydrolyzate and lignin. Background technique [0002] Lignocellulosic biomass includes agricultural production waste and residues (such as crop straw, chaff, corncob, bran, bagasse, etc.), forest wood (softwood and hardwood) and forestry processing waste, grass, etc. The most abundant and cheapest renewable resource on earth. The main organic components of lignocellulosic raw materials include cellulose, hemicellulose and lignin. Among them, cellulose is mainly composed of glucose molecules linked by β-1,4 glycosidic bonds. Glucose can be produced by hydrolysis Hemicellulose is composed of polypentose, polyhexose and polyuronic acid, which can be hydrolyzed to produce xylose, arabinose, galactose, etc.; lignin is a natural polymer compound compo...

AI Technical Summary

Problems solved by technology

However, concentrated sulfuric acid and concentrated hydrochloric acid are highly corrosive, require high equipment materials, and are seriously poisonous to the environment. Separation, recovery and re-concentration greatly increase the complexity and cost of the process.

(2) Dilute acid hydrolysis method generally adopts dilute sulfuric acid, dilute hydrochloric acid and dilute nitric acid (such as Chinese patents 200710029054.0, 02145150.8), which need to be hydrolyzed for a long time at high temperature (100-220 ° C), and dilute acid hydrolysis often only acts on half Cellulose can’t hydrolyze cellulose, nor can it remove lignin. The yield of hydrolyzed sugar is generally lower than 50%, accompanied by the degradation of monosaccharides. There are many by-products, which are harmful to fermentation. Various detoxification methods and processes are required. complex

(3) Organic acid hydrolysis generally adopts organic strong acids with low boiling points such as trifluoroacetic acid and trifluoromethanesulfonic acid (such as Chinese patent 200710037882.9), which can degrade hemicellulose into oligosaccharides and monosaccharides, and recover organic strong acids by distillation , but the hydrolysis time is longer (1-12 hours), the fluorine-containing organic strong acid is highly toxic, and the residues of trifluoroacetic acid and trifluoromethanesulfonic acid are very harmful to fermentation

The pretreatment means of present patent report comprises the following methods: (1) steam explosion method, process biomass raw material with high-pressure saturated steam (as U.S. Patent US4070232), then suddenly reduce pressure, make raw material burst and degrade, cause hemicellulose to degrade, make The solubility of cellulose is increased, but this method has less lignin dissolution, involves high-pressure equipment, and has high investment costs

(2) Dilute acid pretreatment method, dilute acid can directly hydrolyze hemicellulose to make the raw material porous, which is beneficial to increase the contact area between cellulose and cellulase, but due to the lignin wrapped in cellulose in the dilute acid treatment process The matrix structure is still tight, the efficiency of enzymatic hydrolysis is still not high, and a large number of inhibitory by-products are still produced during the pretreatment process. Multiple detoxification methods are required, and the process is complicated.

(4) Alkali pretreatment method, according to the characteristics that lignin can be dissolved in alkaline solution (such as sodium hydroxide, ammonia solution), using OH - Weaken the hydrogen bond between cellulose and hemicellulose and the ester bond between saponified hemicellulose and lignin molecules, resulting in a decrease in the degree of polymerization and crystallinity of cellulose, and destroying the structure of lignin (such as Chinese patent 200710175743.2) , but the alkali treatment process requires long-term high-temperature cooking, the loss of sugar is large, the alkali cannot be recovered, and there are still problems such as neutralization and washing

(5) Organic solvent method, utilizing lignin to be easily soluble in organic solvent, after adopting other methods to destroy the binding layer of lignin and hemicellulose and cellulose, use organic solvent to extract lignin, and reclaim organic solvent by distillation, Commonly used organic solvents include ethanol, methanol, acetone, and acetic acid (such as Chinese patents 200710029054.0, 200710037882.9), but these solvents are miscible with water, difficult to separate phases, low solvent recovery rate, and low lignin purity. There are also patents that use organic solvents for high-temperature cooking Extract lignin (such as Chinese patent 200710175743.2), long time, high temperature, high energy consumption (100-200°C, 0.5-6 hours)

(6) Other pretreatment methods, such as ozone treatment, oxidation treatment, biological treatment, etc., but these methods lack competitiveness due to immature technology, high cost or low efficiency

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