Succinic acid production by Anaerobiospirillum succiniciproducens: effects of the H2/CO2 supply and glucose concentration

Abstract

Several environmental factors affecting the succinic acid production by Anaerobiospirillum succiniciproducens were studied. External CO2 supply had a negative effect on cell growth at both pH 6.2 and pH 6.5, while it had a somewhat positive effect on succinic acid production. The effect of CO2 on succinic acid yield was higher at pH 6.5 than pH 6.2. External supply of H2 enhanced the cell growth rate and succinic acid yield. The optimum ratio of H2/CO2 was 5:95% (v/v) when 20 g l−1 glucose was used. Under this condition, succinic acid yield and productivity were 91% and 1.8 g l−1 h−1, respectively. The formation of the byproduct was not much influenced by the external supply of H2. The distribution of the fermentation products was not affected by varying the initial glucose concentration in a reasonable range, but the succinic acid yield and productivity were higher at 40 g l−1 glucose. It was concluded that the external supply of CO2 and H2 at the optimum ratio makes it possible to produce succinic acid with a high yield and productivity.