Chapter

Corynebacterium glutamicum

Volume 23 of the series Microbiology Monographs pp 107-147

Date:

Amino Acid Production by Corynebacterium glutamicum

  • Masato IkedaAffiliated withFaculty of Agriculture, Department of Bioscience and Biotechnology, Shinshu University Email author 
  • , Seiki TakenoAffiliated withFaculty of Agriculture, Department of Bioscience and Biotechnology, Shinshu University

* Final gross prices may vary according to local VAT.

Get Access

Abstract

During the half century following its discovery, the l-glutamate-producing microorganism Corynebacterium glutamicum has played a leading role in the amino acid fermentation industry. Due to its importance as an amino acid producer, C. glutamicum is also one of the best-investigated microorganisms, evidenced by the extensive body of relevant literature and patents. In the past quarter century, various genetic engineering tools and global analysis techniques for this bacterium have been developed and successfully applied, giving a thorough understanding of its physiology and permitting the development of efficient production strains. The advances enhancing the usefulness of this bacterium for amino acid production over the last decade can be summarized in five points: (1) Metabolic engineering strategies are expanding from the core biosynthetic pathways to include central metabolism, cofactor-regeneration systems, uptake and export systems, energy metabolism, global regulation, and stress responses; strain improvement is bound to thereby optimize entire cellular systems. (2) Systems biology for this bacterium is almost capable of predicting targets to be engineered and metabolic states that will yield maximum production; these developments should allow rational metabolic design. (3) Rapid strides in genome analysis have revolutionized strain improvement methodology, allowing reengineering of more efficient producers through knowledge of the mutations that have accumulated over years of industrial strain development. (4) The spectra of both products and assimilable carbon sources of this bacterium have expanded, leading to the development of, e.g., production strains of serine and methionine that could not be produced effectively from glucose and strains that can utilize alternative feedstocks that do not compete with human food or energy sources. (5) Recent identification of a putative mechanosensitive channel as a possible glutamate exporter has provided valuable insight into the glutamate production mechanism which had long been the central question concerning the industrial biotechnology of C. glutamicum. This chapter describes advances in the production of amino acids by C. glutamicum, with special focus on the technology and strategies for molecular strain improvement.