Effect of Overexpression of Heterologous Pyruvate Carboxylase on Succinic Acid Production in Lactobacillus plantarum

Abstract

　Succinic acid is mainly synthesized by chemical methods. However, alternative production methods such as fermentative production in biomass are desirable. Metabolically engineered lactic acid bacteria (LAB) are being increasingly recognized as novel producers of useful compounds. Among LAB, Lactobacillus plantarum NCIMB 8826 is an interesting candidate that can be used for succinic acid production by metabolic engineering since it has an incomplete tricarboxylic acid (TCA) cycle. We examined if the overexpression of heterologous pyruvate carboxylase (PC) could improve the metabolic flux from glycolysis to the reductive TCA cycle in a lactate dehydrogenase-deficient strain of Lb. plantarum NCIMB 8826 (VL103). We investigated the effects of the overexpression of PC from Corynebacterium glutamicum ATCC 13032 and PC from Lactococcus lactis IL1403 on the succinic acid production in Lb. plantarum VL103. Lb. plantarum VL103 expressing Lc. lactis IL1403-PC showed a succinic acid production similar to Lb. plantarum VL103. The highest yield of succinic acid was obtained through overexpression of PC from C. glutamicum ATCC 13032 in Lb. plantarum VL103. This recombinant strain produced a 19.9-fold higher amount of succinic acid than the Lb. plantarum VL103 and converted 22.0% of glucose to succinic acid.