Succinic acid production with Escherichia coli AFP111 recovered from fermentation

During the anaerobic fermentation by Escherichia coli AFP111 for succinic acid production, the viable cell concentration and productivity were decreased with the raising of succinic acid concentration. In order to restore cellular succinic acid productivity and prolong fermentation time, we collected strains and refreshed medium for repetitive succinic acid production. However, productivity is lower than that in the anaerobic fermentation before reusing strains. To enhance the productivity, strains were aerobically cultivated for 3 h in pure water before anaerobic fermentation. The activities of key enzymes were enhanced for better performance in producing succinic acid at anaerobic stage. After three rounds of repetitive fermentations, succinic acid concentration and yield reached to 56.50 g/L and 90% respectively. The succinic acid productivity was 0.81 g/(L·h), which was 13% higher than the repetitive fermentations without aerobic activation of the strains.