Study On The Ethanol Fermentation Of Hydrolysis Of Biomass

A strain B03 fermenting xylose into ethanol was obtained with xylose as the carbon source. The ethanol concentration of fermentation hydrolysis was15.2g/L, ethanol yield is 66.2% and the xylitol accumulation was 3.9g/L of B03 under the optimum conditions. And studying the tolerance of fermentation inhibitors and ethanol of B03.The results showed that the maximum tolerance concentration of acetic acid, furfural and ethanol was 4.5g/L,2.0g/L, and 72g/L respectively, the effect of levulinic acid was not obvious.Mutant strain B03-13 was gotten which had the highest yield of ethanol by fermenting the hydrolysate by mutagenized the starting strain B03. Compared the difference of xylose reductase and xylitol dehydrogenase between B03 and B03-13, finding the activity of xylose reductase and xylitol dehydrogenase of the mutant strain B03-13 were both higher than the starting ones B03, while the XR/XDH of B03-13 is smaller than the starting ones B03. The ethanol concentration of fermentation hydrolysis was 18.3g/L, ethanol yield is 79.7% and the xylitol accumulation was 1.2g/L of B03-13 under the optimum conditions. And studying the tolerance of fermentation inhibitors and ethanol of B03.The results showed that the maximum tolerance concentration of acetic acid, furfural and ethanol was 5.0g/L,1.8g/L, and 80g/L respectively, the effect of levulinic acid was not obvious. The optimal process conditions was gotten of B03-13 by response surface analysis, and the optimal medium composition was gotten of B03-13 by orthogonal experiments.Flora B00 was achieved on the basis of pure fermentation bacteria. Compared the difference between B00 and B03, the results showed that B00 adapt to a wider range of initial pH, temperature, rotation speed and substrates, and B00 could better tolerate the fermentation inhibitors, therefore more suitable to industrialization.