Utilization Of Straw-degrading Microorganisms And Study Of Polysaccharide Product

In order to realize the further utilization of straw resource and solve the problem of low straw utilization rate and pollution caused by the burning of straw, in the text a further choose was made during straw-degrading microorganisms screened by the lab, the fermentation conditions of producing polysaccharide by the degradation of straw was optimized and the structure of the polysaccharide was studied.The further choose of efficient straw-degrading microorganisms:the straw degradation rates of two floras, three straw-degrading strains and composite flora composed of the three strains were determined with ash tracer method and comparison comprehensively. The optimization of fermentation conditions to produce polysaccharide by degrading straws: the text was designed with Minitab software. By Plackett-Burman design, Steepest ascent design, Central composite design and Response surface methodology, the regression equation was established, then the optimal fermentation conditions was worked out. Physical and chemical properties and structure of the polysaccharide: After ethanol precipitation to extract the polysaccharide in the fermented liquid and the further purification, a polysaccharide called FFSP was obtained. The structure, physical and chemical properties of FFSP were studied using analysis technologies such as IR spectra, UV spectra, TLC, GC-MS, etc.The results of tests were as follows:The further choose of efficient straw-degrading microorganisms:The method by ash tracer to determine microbial degradation rate of straw was simple for operation, could accurately determine the straw degradation rate. By the method, the flora called7#with the highest ability of straw degradation was confirmed, with a degradation rate reached49.53%.The optimization of fermentation conditions to produce polysaccharide by degrading straws:the optimized condition was that fermentation time was12.2897d and straw content was50.4398g/L. In this condition a maximum polysaccharide yield of2159.23mg/L could be reached, which was as twice as the original (1078.63mg/L).Physical and chemical properties and structure of the polysaccharide: FFSP showed general characteristic absorption peaks of the carbohydrate material, as well as beta pyranoside bonds; did not contain starch, nucleic acids, proteins amino, acids and polyphenols; was with long side chain and more branches; might have a three-screw structure. Monosaccharide composition:galactose, mannose, glucose, arabinose, xylose and rhamnose.Degradated straws can be used as fertilizers. Polysaccharide shows a variety of pharmaceutical and chemical value. This study provides theoretical and methodological basis for the further development of the resource of corn straws.