Novel process for jointly degrading and saccharifying crop straw by means of thermo-chemical treatment, microbial fermentation and enzymatic hydrolysis

Abstract

The invention relates to a novel process for jointly degrading and saccharifying crop straw by means of thermo-chemical treatment and enzymatic hydrolysis. The novel process includes steps of 1), mixing the smashed crop straw and soak liquid with each other according to a solid-to-liquid ratio of 1g:9-13ml to obtain mixtures, then carrying out heat-insulation treatment on the mixtures at the temperature of 70-90 DEG C for 6-18h, adding hydrogen peroxide into the mixtures after the heat-insulation treatment is completed, keeping the mixtures at the temperature of 50 DEG C for 6-18h, and fetching and drying the mixtures; 2), transferring the straw obtained in the step 1) into distilled water, adding straw with 20-60 FPU / g of cellulase and straw with 300-600U / g of xylanase into the straw, regulating the pH (potential of hydrogen) of the straw until the pH reaches 4-5, then carrying out enzymatic hydrolysis by the aid of shaking tables at the temperature of 45-50 DEG C for 24-48h, treating the straw at the temperature of 100 DEG C for 30min after enzymatic hydrolysis is completed so as to terminate enzymatic hydrolysis reaction and drying and smashing enzymatic hydrolysis products. The volume of the hydrogen peroxide is 3% of that of the soak liquid. The soak liquid is a lime supernatant with sodium hydroxide, the sodium hydroxide accounts for 2% of the weight of the crop straw, and lime accounts for 5-15% of the weight of the crop straw. The novel process has the advantage that the degradation rate of the straw and the reduced sugar yield (442.85mg / g) of the straw can be obviously increased.

Description

technical field [0001] The invention belongs to the technical field of crop straw treatment, and in particular relates to a new process for degrading and saccharifying crop straw in combination with thermochemical treatment, microbial fermentation and enzymatic hydrolysis. Background technique [0002] Straw lignocellulose, as a structural carbohydrate, is a huge amount of renewable resources that exist in nature. However, due to the lack of effective treatment methods, most straw resources are burned or buried in farmland as waste. Straw is mainly composed of cellulose, hemicellulose and lignin. Through microbial fermentation and enzymatic hydrolysis, cellulose and hemicellulose can be converted into glucose monomer, ethanol, furfural, animal feed, energy and other chemical raw materials. However, the complex three-dimensional macromolecular network aromatic polymer of lignin hinders the access of cellulase to cellulose polymer. Therefore, how to decompose lignin to impro...

AI Technical Summary

Problems solved by technology

However, straw is developed as animal feed, and high-concentration chemical treatment will not only damage the health of animals, but also cause environmental pollution and increase costs due to the need for a large amount of water to wash the processed products.

Previous studies on acid and alkali treatment of straw to produce ethanol have made remarkable achievements, but due to chemical ions (Na + , Ca 2+ and Cl - ) exceeding animal nutrition standards are not suitable for feed production

Organic solvents such as dimethyl sulfoxide, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolidinone can be used as co-solvents to treat straw, but these treatments are harmful due to the addition of toxic and harmful chemicals. animal health hazard

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