Optimization for Enhanced Production of Antibacterial Metabolites by Marine Actinomycetes Kocuria sp. strain rsk4

Abstract

A new halophilic actinomycetes strain was characterized and on the basis of hysiological and 16S rDNA sequence, it was designated as Kocuria sp. strain rsk4. It was able to produce antibacterial metabolites and shows broad spectrum antibacterial activity against several gram-positive and gram-negative bacteria. Rsk4 showed highest antagonistic effect against multi drug resistant bacteria Staphylococcus aureus. Cultural and nutritional conditions of strain have been optimized under shake-flask conditions for the efficient production of antibacterial metabolites. Among the various factors, starch casein medium, 30ºC temperature, neutral pH, 5% salinity, 7 days incubation period and 180 rpm agitation was found to be optimal for antibacterial metabolite production. 1% starch, yeast extract, casein and magnesium were found to be best carbon source, nitrogen sources and mineral respectively for improved antibacterial activity. Among various combinations of nitrogen source, yeast extract and casein in equal ratio showed enhanced antibacterial activity. This is the first report on the optimization of antibacterial metabolites by Kocuria sp. The study suggests that the Kocuria sp. could scale up by traditional method for production of antibacterial metabolites effective against multiple drug resistant S. aureus.