The present study was undertaken to investigate the antibacterial potential of a bacterium BSA1 isolated from the gut of common carp Cyprinus carpio against human bacterial pathogens. Polyphasic test results revealed that the candidate bacterium BSA1 belongs to the genera Bacillus sp. Effect of different production media on antibacterial activity inferred that Bacillus sp. grown in YBPD medium had pronounced antibacterial activity (2 and 8 mm) than other media tested. Effect of various media components on antibacterial activity substantiated that mannitol (3 to 14), peptone (2 to 10 mm), 3% inoculum (3 to 10 mm) and 40°C (2 to 6 mm) had effectively enhanced the growth of bacterium with appreciable inhibitory zones. Statistical analysis of antibacterial activity through ANOVA suggested that inhibitory zones significantly varied due to different between bacterial strains and media components. Further studies on the effect of pH, vitamins, surfactants, NaCl (%) and a thorough statistical media optimization protocol may yield suitable media for growth and bioactive metabolite by Bacillus sp.

Keywords : Bacillus sp.; Media optimization; Antibacterial activity.