Succinic acid production by repeated batch fermentation based on high density culture

Succinic acid production by repeated batch fermentation based on high density culture was studied.The result showed that E.coli could convert glucose to succinic acid in aqueous solution of glucose and a neutralizer.When cell density increased approximately to 28 g·L-1(DCW),the aerobically grown cells were directly brought into anaerobic conditions.Glucose concentration was maintained at about 10 g·L-1 with constant flow feeding.Cells were recycled from final fermentation broth for the next batch of repeated fermentation when the last fermentation was stopped at 30 h.After two-stage fermentation and two cycles of cell reincubation,the concentration of succinic acid was 95.1 g·L-1,79.7 g·L-1 and 64.4 g·L-1 respectively.The average succinic acid yield and productivity were 72.5% and 1.93 g·L-1·h-1 respectively,with an increase of 29.5% and 25.9%,compared with those in the two-stage fermentation.