Succinic acid production with metabolically engineered <Emphasis Type="Italic">E. coli</Emphasis> recovered from two-stage fermentation

Escherichia coli AFP111 cells recovered from spent two-stage fermentation broth were investigated for additional production of succinic acid under anaerobic conditions. Recovered cells produced succinic acid in an aqueous environment with no nutrient supplementation except for glucose and MgCO₃. In addition, initial glucose concentration and cell density had a significant influence on succinic acid mass yield and productivity. Although the final concentration of succinic acid from recovered cells was lower than from two-stage fermentation, an average succinic acid mass yield of 0.85 g/g was achieved with an average productivity of 1.81 g/l h after three rounds of recycling, which was comparable to two-stage fermentation. These results suggested that recovered cells might be reused for the efficient production of succinic acid.