Abstract: The optimization of medium components for improved succinic acid production by Actinobacillus succinogenes GXAS137 at reduced cost was performed using one-factor-at-a-time method and response surface methodology. The independent variables considered were electron acceptors, crude glycerol concentration and nitrogen sources. The results showed that dimethyl sulfoxide (DMSO) was the optimum electron acceptor and corn steep liquor (CSL) could be used as an alternative nitrogen source to replace yeast extract. The optimum culture medium that provided maximum succinic acid yield of 37.02 g/L, which was increased by 119% compared to that (16.88 g/L) before optimization, was composed of crude glycerol 55.43 g/L, DMSO 10.35 g/L and CSL 17.69 g/L. Under this optimized condition, the conversion rate of glycerol to succinic acid was 66.79% and succinic acid productivity was 0.51 g/(L·h). This study can provide a basis for the microbial production of succinic acid from crude glycerol.

Key words: Actinobacillus succinogenes GXAS137, crude glycerol, succinic acid, one-factor-at-a-time experiments, response surface methodology