Fermentation characteristics of engineered Escherichia coli for succinic acid production

Succinic acid produced by microbial fermentation has much environmental benefits and attracted great interest currently. Among them, Escherichia coli have been chosen as good succinic acid producing strains because of their advantages. Normally, no more than 0.2 mol of succinate is formed per mol of glucose consumed by E. coli. In order to improve the yield of succinic acid, a genetically modified E. coli JH204 was constructed through RED recombination system and the flipase recognition target (FRT) site-specific recombinant technology, and multi-genes were knocked out from wild strain E. coli W, including ldhA, adhE, pflB, poxB and ackA to block the metabolic competition pathways. In this paper, the fermentation characteristics of the succinic acid production by engineered strain was investigated. The mutant carries out a favorable fermentation of glucose in 10L fermenter, and the production of succinic acid was approximately 40.08g/L, and the productivity and yield were 0.83gL^-1h^-1 and 0.72g/g glucose respectively. Acetic acid and lactic acid were the only products detected and accumulated to concentrations of 4.53g/L and 0.08g/L, respectively. And formic acid and ethanol were not detected in the medium of the fermentation.