Production Of2,3-Butanediol From Corncob By Simultaneous Saccharification And Fermentation Process

2,3-butanediol is widely used in chemical, food, fuel and other fields. The production of2,3-butanediol by Klebsilla oxytoca ZU-03under simultaneous saccharification and fermentation(SSF) process from corncob were studied in this paper.Outstanding factors during the SSF process such as the dosage of enzymes, pH, temperature and substrate concentration was optimized for better2,3-butanediol production.The suitable condition was as followed:(for1gramme corncob) cellulase25FPIU,cellobiolase15IU,xylanase300IU, pH6.0,36℃.And when the initial substrate concentration was120g/L, through a36h SSF process,2,3-butanediol turned out to reach46.03g/L with a1.28g/(L·h) productivity and a conversion rate for0.424g/g.Fed batch fermentation method which was frequently used for increasing the final product concentration and lower the followed extracting cost was also discussed here as for the proper supplementation and substrate concentration. It was proved the best that when the substrate corncob to corn liquor was at the rate10:2and15g/L of that was added to batch fermentation every12hours after incubation. After the starting100g/L substrate was supplemented to250g/L and a144h SSF process, the finial2,3-butanediol reached75.65g/L, which possessed a60%enzyme reduction for every1gramme substrate as compared with the traditional SSF technique.After fermentation the broth was carried out a FeCl3flocculation for solid-liquid separation and a further sodium citrate/ethanol two-phase system downstream extraction. On the basis of single-factor test, the separation process was optimized by the response surface analysis, and three key factors-fhe mass fraction of sodium citrate and ethanol, temperature were selected to do Box-Benhnken central composite tests. Through the response surface analysis, the result was that:91.8%2,3-butanediol could be extracted when the mass fraction of sodium citrate and ethanol respectively21%and25%at38℃, and90.6%protein in the broth was removed.Production of2,3-butanediol from renewable plant fiber instead of food has important economic and social significance.