Abstract
Recombinant Escherichia coli NZN111 ($F-{\Delta}pfl::Cam$ ldhA::Kan) harboring pTrcML, a plasmid containing the E. coli malic enzyme gene, produced considerable amount of malic acid along with the desired product succinic acid. This seemed to be due to the unmatched redox states between glucose and succinic acid. Therefore, a more reduced carbon substrate sorbitol was examined for the possibility of matching the potential during succinic acid production. When NZN111 (pTrcML) was cultured in LB medium containing 20 g/L sorbitol under $CO_2$ atmosphere, 10 g/L of succinic acid was produced. The apparent yield of succinic acid was 1.1 g succinic acid per g sorbitol, which is 85% of the maximum theoretical yield.
