서강대학교

초록/요약

Biological utilization of synthesis gas is a competitive and potential technology for the fuel ethanol production. As a biorefinery platform, this technology has a prominent advantage of low energy consumption. Production of ethanol and acetate could be implemented by fermenting CO/H2 or CO2/H2 at ambient temperature and atmospheric pressure. In this study，ethanol and acetate was produced by using Clostridium autoethanogenum, a strictly anaerobic bacterium, in a stirred tank reactor (STR). A two-stage syngas fermentation operating mode was developed: (1) a growth stage using cell-recycling and fructose as a carbon source at pH 6.0, allowing high concentration of microbial cell population; (2) a production stage at pH 5.5 to convert syngas and acetate into ethanol. In conclusion, we successfully carried out the fermentation process by C. autoethanogenum converting gaseous substrate to ethanol in a STR with cell-recycling. Maximum optical density was 21.68 of OD600nm in 5.4 days, ethanol and acetate concentration reached 23.0 g/L and 10.5 g/L respectively in 14.7 days with syngas composition 15%‬ CO, 45% H2 and 40% N2.