Overexpression of fumarase to enhances succinate production by C.acetoacidophilum

• 1、College of biological engineering，Jiangnan university，Wuxi，Jiangsu 214122

Abstract：Succinic acid is a potential bulk chemical. In this work, the fumarase gene derived from Actinobacillus succinogenes were successfully expressed in Corynebacterium acetoacidophilum ATCC 13870 to obtain a genetically engineered strains Δldh / fum and △ ldh / pyc / fum, and used for succinic acid production by fermentation.The results shown that the introduction of exogenous fumarase can significantly increase the cell specific growth rate and biomass. As well as the carbon flux to the formation of succinic acid was increased by more than 10% when fermented under oxygen deprived condition. A two-stage fermentation was performed on a 3 L fermenter, in which aerobic culture was carried out until cell growth at the stable phase, then glucose and sodium bicarbonate were added with the initial pH was less than 8.2, which was converted to oxygen limiting fermentation. Under the conditions of aeration of 0.05 vvm, temperature of 30 ℃, rotation speed of 380 r / min, and pH 7.6 for 90 h fermentation, the concentration of succinic acid reached 108 g / L. It is shown that overexpression of fumarase is an effective way to increase the production of succinic acid by Corynebacterium acetoacidophilum.

Keywords： Succinic acid Corynebacterium acetoacidophilum Actinobacillus succinogenes Fumarase Fermentation