Bacteriocins are a special interest due to their potential value as natural preservative. The present study is a factual production of such bacteriocin from marine Lactobacillus sp. Lactic acid bacteria (LBA) was isolated from fish gut of the Sardinella longiceps and their density was found to be 4.8 x 10⁷ respectively. Various pathogens were also isolated from pickle. LAB strains were optimized at different parameters and maximum bacteriocin production was at pH 5, temperature of 35°C, 3.5% of salt concentration with 24^th hour of incubation period. Lactobacillus casei was screened as the most potential strain for both bacteriocin production as well as antimicrobial activity. FT-IR spectrum also confirmed the obtained protein as a bacteriocin. The present study has revealed that Lactobacillus strains from marine origin are having the potential properties as a biopreservatives especially in seafood industries with large scale production for commercial utilization.