Experiments were carried out to find the efficiency of Brevibacterium sp. to utilize different carbon sources (glucose, fructose, sucrose, maltose, lactose, xylose and starch) for its growth and for the production of glutamic acid. Except starch, all the carbon sources supported the growth of the culture, which showed a preferential choice of growth and activity when grown on glucose as sole carbon source. Mixed substrate fermentation did not improve the yield of amino acid. Maximum glutamic acid yields (6.86 mg/ml) were obtained when 2% glucose medium was fermented under optimized conditions for 48 h.The establishment of L-glutamic acid fermentation provided a significant impetus to the development of microbial production of primary metabolites. Selection of suitable carbon source and its concentration in fermentation medium is of utmost importance in amino acid production. The production yield seems to be largely influenced by the carbon source in the culture medium (SUGIMOTO and SHUO 1989). When amino acids are produced from different carbon source, the yields are strongly affected by the metabolic pathways specific to respective carbon source and the regulatory mechanisms on the pathways (SHIIO et al. 1990). L-glutamic acid production by Brevibacteriumflavum mutant M-128 from glucose, fructose, sucrose and from the mixed substrate fermentation was not so strongly affected by these carbon sources while L-phenylalanine production was greatly affected (SHUO et al. 1990). Glutamate can also be produced from carbon sources other than sugars like, hydrocarbons (KOBAYASHI et al. This paper deals with the effect of different carbon sources on growth and glutamic acid fermentation by a strain of Brevibacterium sp.
Materials and methodsOrganism and culture medium: A strain of Brevibacterium sp. DSM 20411 was used in the present studies. Culture was grown on a medium containing (gA) casein peptone 10.0, yeast extract 5.0, glucose 5.0, NaCl5.0, agar powder 15.0 and distilled water (pH 7.2-7.4). Slants were prepared and stored at 4 "C and renewed twice a month.