Bacteria Genomes - CORYNEBACTERIUM EFFICIENS

Coryneform bacteria are rod-shaped, fast growing, non-sporulating Gram-positive bacteria that enjoy widespread distribution. Corynebacteria are used commercially to produce amino acids. Since the discovery, in the 1950s, that these bacteria could produce large amounts of glutamic acid, researchers have genetically modified strains to increase their yields.

Phylogenetic studies, based on 16S rDNA analysis, demonstrated that three strains formed a distinct cluster within the genus Corynebacterium, and that their nearest relatives were Corynebacterium glutamicum and Corynebacterium callunae, also known as glutamic-acid-producing species. The data from 16S rDNA sequence and DNA-DNA related studies clearly indicated that the three isolates represented a new species within the genus Corynebacterium. All of the isolates could grow at 45C and produced acid from dextrin. On the basis of this data it was proposed that the three glutamic-acid-producing isolates together be classified as Corynebacterium efficiens sp. nov.

Worldwide there is a huge demand for Monosodium-glutamate (MSG) as a flavour enhancer, in 1996 worldwide production exceeded 1 million tonnes and much of it is produced using Corynebacterium. This causes a problem in that the amount of heat generated kills the bacterium unless complicated cooling systems are installed. In Japanese trials evidence has shown that C. efficiens can produce MSG at a temperature of 45C, this could result in more efficient and cheaper production.

References:

http://www.genomenewsnetwork.org/sequenced_genomes/genome_guide_p1a.shtml
Int. J. Syst. Evol. Microbiol. 52, 1127-1131 (2002)
http://www.socgenmicrobiol.org.uk/QUA/080212.pdf