Metabolic engineering of Corynebacterium glutamicum for L-valine production.

Abstract

Abstract L-Valine is one of the three branched-chain amino acids that is essential for animal health and important in metabolism, so it is widely added to food, medicine and feed products. It is predominantly produced through microbial fermentation, and the production efficiency largely depends on the quality of the microorganisms used. In recent years, continuing efforts have been made to determine the mechanisms and means of regulation of L-valine biosynthesis in C. glutamicum, the bacterium that is most used for amino acid production. Metabolic engineering based on the mechanisms of biosynthesis and regulation of L-valine production in C. glutamicum provides an effective alternative to traditional breeding for strain development, and industrially competitive L-valine-producing C. glutamicum strains have now been constructed by genetically defined metabolic engineering. This article reviews the global metabolic and regulatory networks responsible for L-valine biosynthesis, the molecular mechanisms of regulation and the strategies employed in C. glutamicum strain engineering.