Metabolic engineering strategy for the malic and fumaric acid production in Mannheimia succiniciproducens

Abstract

Fumarate and malate commonly used chemicals and are closely associated with everyday life. A Gram-negative rumen bacterium, Mannheimia succiniciproducens, produces mainly succinate using anaplerotic pathway under anaerobic condition. The wild type M. succiniciproducens can’t produce malate and fumarate, but M. succiniciproducens ideal for producting fumarate and malate because its strong anaplerotic pathway under CO2 condition. Recently, our group published papers about developing the high succinate production strain by gene knock-out. Based on this strain, fumarate and malate producing strains were constructed. Especially, when fumarate reductase was knock-out, the strain was found to produce malate and fumarate and not succinate. The results provide useful information for the rational metabolic engineering by optimizing metabolic fluxes to improve fumarate and malate production in species with strong anaplerotic pathway