In this study, bacterial strains were isolated from curd and evaluated its bactericidal potential against two aquatic pathogens Salmonella sp and Vibrio sp isolated from marine fish, Parastromateus niger and squid, Loligo duvauceli. Based on the antimicrobial activity, potential strain was selected and identified as Bacillus sp. Further, bacteriocin was partially purified from the Bacillus sp by ammonium sulphate precipitation and dialysis. The molecular weight of the partially purified bacteriocin was estimated by SDS-PAGE. To understand the biopreservative ability of the purified bacteriocin, tissues of Salmonella and Vibrio-infected fish, Parastromateus niger and Loligo duvauceli were treated with bacteriocin for 30 days at different storage conditions (-4°C and -20°C) and the microbial load was counted at 5, 10, 15, 20, 25 and 30 days. Results showed that bacteriocin significantly reduced the total bacterial count at both storage temperatures in a time dependent manner. This study proved the efficiency of bactericidal and biopreservative activity of bacteriocin isolated from Bacillus subtilis (KY808492).
Ashwitha A, Thamizharasan K, Vithya V, Karthik R and Vijaya Bharathi S