Antimicrobial activity of bacteriocin from lactic acid bacteria against fish bacteria

Elamparithi, P and Ramanathan, N

Lactic acid bacteria (LAB) are most commonly used microbiology for preservation of foods. Bacteriocins are proteinaecous substances produced by many bacterial strains and exhibit bactericidal activity against the closely related organisms. They have been the subject of extensive studies in recent years because of their prospective use as natural food preservatives (Villiani et al., 2001). Lactic acid bacteria (LAB) are widespread in nature and predominate in microflora of milk and its products. LAB is known to produce bacteriocins and have great potential as food bio preservations (Gilliland, 1990, Jamuna, Jeeveratnum, and Avonts et al., 2004). Bacteriocins are peptides with antimicrobial activity that are secreted by some bacteria to inhibit the growth of other competing microorganisms. Antimicrobial activity of crude Bacteriocin lactic acid bacteria (LAB) isolation of Lactobacillus acidophilus was tested for its antimicrobial activity of Pseudomonas sp, Flavobacterium sp, Shewanella sp, Vibrio parahaemolyticus and Vibrio vulnificus isolated from fish. The methods used for testing the antagonistic effect on the pathogens are agar diffusion assay, Minimal inhibitory concentration, Minimal Bactericidal concentration test. This study revealed that inhibition of growth for fish bacteria was obtained in 100µl in the well diffusion test. In MIC the higher inhibition of growth was found in 2.8ml for Vibrio parahaemolyticus, 2.4ml for Vibrio vulnificus, 2.2ml for Pseudomonas sp, 2.0ml for Shewanella sp, and 1.8ml for Flavobacteria sp, whereas; In MBC the higher inhibition of growth was found in 3.0ml for Vibrio parahaemolyticus, 2.8ml for Vibrio vulnificus, 2.6ml for Pseudomonas sp, 2.4ml for Shewanella sp, and 2.2ml for Flavobacteria, respectively.