Studies On Improving Alcohol Yield Utilizing Cassava As Raw Material

The content of amino nitrogen of yellow serofluid was improved with the action of acid protease, the processed yellow serofluid is beneficial in improving yield of ethanol when it is utilized as nutrient of nitrogen source of ethanol fermentation with cassava as the raw material. The proper addition of Mg2+,Zn2+ can promote ethanol fermentation with yeast. brankoji can be used as the promoter of ethanol fermentation.The experimental results showed that:(1) By single factor experiment of hydrolyzing yellow serofluid with acid protease, the optimal conditions was confirmed as follows: adding volume of enzyme was 40u/mL, pH3.0,time of enzyme hydrolysis was 10h,reaction temperature was 40℃. The orthogonal experiment showed the optimal conditions was confirmed as follows: adding volume of enzyme was 35u/mL, pH3.0,time of enzyme hydrolysis was 12h,reaction temperature was 40℃. The content of amino nitrogen in yellow serofluid was improved to 156.6% according to the experimental scheme confirmed above.(2) The yellow serofluid used as nitrogen source of seeding yeast cultivation outmatch carbamide and ammonium bisulfite. The cell concentration in fermentation broth improved by 18% and 14% when yellow serofluid was used as nitrogen source compared with that of carbamide and ammonium bisulfite respectively. The field of ethanol improved by 2.2% and 1.7% when yellow serofluid was used as nitrogen source compared with that of carbamide and ammonium bisulfite respectively. The yellow serofluid which is a kind of waste water in distilled spirit plants can be recycleld, which not only lessen the pressure of waste water treatment in distilled spirit plants, but improve the ethanol production.(3) Under the condition of laboratory, Mg2+and Zn2 can promote the fermentation of ethanol by yeast, and the optimal adding volume is 250 and 500mg/L respectively.enen a little bit of K+ or Fe2+ can inhibit ethanol fermentation.(4) The ability of Saccharomyces cerevisiae tolerant to ethanol improved by 3 degree when brankoji was added. The ethanol fermentation time reduced 6h when brankoji was added. The concentration of ethanol in fermentation broth increased obviously , the concentration of ethanol improved by 1.1 degree and the relative ethanol production rate increased by 3.1% when the adding volume was 2%.