Continuous succinic acid fermentation by Actinobacillus succinogenes in a packed-bed biofilm reactor

Background: Succinic acid is one of the most interesting platform chemicals that can be produced in a biorefinery approach. In this study, continuous succinic acid production by Actinobacillus succinogenes fermentation in a packed-bed biofilm reactor (PBBR) was investigated. Results: The effects of the operating conditions tested, dilution rate (D), and medium composition (mixture of glucose, xylose, and arabinose - that simulate the composition of a lignocellulosic hydrolysate) - on the PBBR performances were investigated. The maximum succinic acid productivity of 35.0 g L^-1 h^-1 and the maximum SA concentration were achieved at a D = 1.9 h^-1. The effect of HMF and furfural on succinic acid production was also investigated. HMF resulted to reduce succinic acid production by 22.6%, while furfural caused a reduction of 16% in SA production at the same dilution rate. Conclusion: Succinic acid production by A. succinogenes fermentation in a packed-bed reactor (PBBR) was successfully carried out for more than 5 months. The optimal results were obtained at the dilution rate 0.5 h^-1: 43.0 g L^-1 of succinic acid were produced, glucose conversion was 88%; and the volumetric productivity was 22 g L^-1 h^-1.