Bacteriocin production by a marine strain of Bacills sp. Sh10: Isolation, screening and optimization of culture condition

Abstract

Antibacterial peptides have emerged as an alternative therapeutic to protect food and other products from deterioration and spoilage. In this study, bacteria were isolated from marine clams and screened for bacteriocin production using cross-streaking and spot-on-lawn methods. One of the isolates, identified as Bacillus species Sh10, produced proteinaceous bacteriocin with a broad spectrum of activity against human pathogens and food-spoilage bacteria. The effect of different media compositions and culture conditions namely, the type and concentration of carbon and nitrogen source, NaCl concentration, temperature, pH, aeration and incubation time on the production of bacteriocin by Bacillus sp. Sh10 was investigated. Optimum bacteriocin production was recorded when 2% tryptone and 1% glucose were added to a basal medium as nitrogen and carbon sources, respectively. The bacteria exhibited maximum bacteriocin production at 2% NaCl, pH 8, 30°C and 200 rev min-1 aeration. Bacteriocin was produced during the stationary phase, indicating it is synthesized as a secondary metabolite. Bacillus sp. Sh10 is able to produce bacteriocin at a wide pH and temperature range making it a good candidate for the production of bacteriocin on an industrial scale level.