CO₂ fixation by Actinobacillus succinogenes in succinic acid production

Actinobacillus succinogenes NJ113 produces succinic acid as a major fermentation end product under CO₂-rich anaerobic conditions. The culture conditions for succinic acid production by fixation CO₂ with Actinobacillus succinogenes NJ113 were studied in a 5 L fermentor. The effects of CO₂ donor, CO₂ flow rate, agitation rate, culture temperature and pH value on CO₂ fixation rate and succinic acid productivity were investigated. The results show that when CO₂ gas is as CO₂ donor, CO₂ flow rate is 0.75 L/min, agitation rate is 200 r/min, culture temperature is 37°C, pH value is 6.6, intracellular CO₂ availability is improved. Under the optimized conditions, CO₂ fixation rate can reach 0.6 g/(L·h) with succinic acid productivity of 1.61 g/(L·h).