A natural symbiotic mixed culture method for degrading roughage to produce citric acid

Abstract

The invention relates to the field of biotechnology renewable energy, in particular to a method for producing citric acid by degrading roughage with a natural symbiotic mixed culture, wherein the mixed culture YakQH5 consists of anaerobic fungi (Neocallimastix frontalis) and methanogens (Methanobrevibacter gottschalkii) Composition, preserved in the General Microorganism Center of China Microbial Culture Collection Management Committee on March 9, 2020, the preservation number is CGMCC No.19299, the mixed culture YakQH5 can degrade 15 kinds of roughage respectively, and produce a large amount of citric acid, Especially when alfalfa is used as the substrate, the citric acid output is as high as 46.0mM. Adding compound antibiotics during the fermentation process can also prevent the mixed culture from being polluted by bacteria during the fermentation process, and further improve the anaerobic fermentation efficiency. The culture YakQH5 has important industrial application value.

Description

technical field [0001] The invention relates to the field of biotechnology renewable energy, in particular to a method for producing citric acid by degrading roughage with natural symbiotic mixed culture. Background technique [0002] Roughage refers to feed with a natural moisture content below 60%, crude fiber content in dry matter equal to or higher than 18%, and fed in the form of air-dried food, such as pasture, crop straw, leaves, distiller's grains, and husks. The main component of roughage is lignocellulose, which has high fiber content, low protein and mineral content, poor palatability, and low digestibility of livestock and poultry, which limits its application. The amount of these roughages produced every year is very huge, such as wheat straw, corn straw, rice straw, oat straw, soybean straw, soybean straw, potato straw, alfalfa, bran, distiller's grains, tomato residue, wheat hulls, etc. They are still used as energy materials. It has not been rationally devel...

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Problems solved by technology

[0005] The inventor first studied the anaerobic fermentation of the co-culture of grazing yak rumen anaerobic fungi and methanobacteria using wheat straw, corn straw and rice straw as substrates (Wei Yaqin. Research on the diversity of culture and its fiber degradation characteristics [D]. 2016.), by detecting gas production, polysaccharide hydrolase activity, various esterase activities, dry matter degradation rate, phenolic acid release, methane and acetic acid production Evaluate the straw degrading efficacy of the co-culture of anaerobic fungi and methanogens, in which the co-culture of anaerobic fungi and methanogens N.frontalis Yak16+M.ruminantium, Piromyces Yak18+M.ruminantium and O.joyonii Yak7+M.ruminantium respectively degrade The yields of acetic acid and methane produced by the three kinds of straws are high, but the yields of citric acid are extremely low, so the data of citric acid are not listed in the doctoral dissertation

So far, there are no reports about anaerobic fungi, or co-cultures of anaerobic fungi and methanogens degrading straw and other roughages to produce citric acid at home and abroad

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