BACKGROUND: Succinic acid is a valuable four-carbon organic chemical with applications in many fields. It was found that cell mass was an important factor in succinic acid production by metabolically engineered Escherichia coli strains. In this work, high cell density fermentation was investigated for succinic acid production by a metabolically engineered strain SD121 with ldhA, pflB, ptsG mutation and heterogenous cyanobacterial ppc overexpression. RESULTS: Under two-stage cultivation, the controlled DO feeding strategy during the aerobic growth phase facilitated biomass up to a dry cell weight of 19.6 g L-1, and enhanced succinic acid production in the following anaerobic fermentation phase to a concentration of 116.2 g L-1. A near theoretical maximum succinic acid yield of 1.73 mol mol(-1) glucose was achieved with an average productivity of 1.55 g L-1 h(-1). CONCLUSION: The results indicated the potential advantage of high cell density fermentation for improvement of succinic acid production by E. coli. (C) 2010 Society of Chemical Industry