A Sequential Co-culture Of Clostridium Thermocellum And Ethanol Or Butanol Producin Bacterium For Corncob Fermentation

Due to the global shortage of grains and petroleum, biofuel production from lignocellulosic biomass through microbial fermentation catches great interests.Ethanol is regarded as one of the most promising environmentally renewable energy resources. A co-culture approach of Clostridium thermocellum ATCC27405and Thermoanaerobacter ethanolicus ATCC31550was investigated for directly converting lignocellulosic substrates to ethanol under anaerobic condition. C. thermocellum was cultured on the medium containing16g·L-1corncob at58℃. At the32th hour, co-culture of C. thermocellum and T. ethanolicus resulted in the efficient utilization of all the hydrolysis products derived from corncob.By maintaining a rather constant pH6.5and feeding of8g·L-corncob at exponential growth phase, the yield of ethanol was6.45g·L-Butanol is an important industrial chemical. It is also recognized as the next generation biofuel that has various advantages over ethanol. A sequential co-culture approach of C. thermocellum and Clostridium beijerinckii NCIMB8052was investigated for directly converting lignocellulosic substrates to butanol under anaerobic condition.C. thermocellum was cultured on the medium containing50g·L-1corncob at60℃for120h. By maintaining different pH in the different stages of fermentation and feeding of55g·L-1corncob at exponential growth phase, a high reducing sugar accumulation of37.4g·L-1was typically obtained in acid-hydrolyzed supernatant. The concentration of pentose and glucose were24.8g·L-1and5.28g·L-1, respectively. Co-culture of C. thermocellum and C. beijerinckii resulted in the efficient utilization of all the hydrolysis products derived from corncob. The yield of ABE (acetone, butanol and ethanol) was16.0g·L-1, of which butanol was8.75g·L-...