Abstract

The aim of this study is to evaluate the production and antimicrobial potential of bacteriocins released by Lactococcus garvieae. Bacteriocins are extracellular in nature having inhibitory activity against other bacteria. The Lactococcus garvieae was isolated from cow’s milk which produces bacteriocins was evaluated by using different media such as MRS (Mann Rogasa Sharpe), M17, Soybean casein digest broth and Brain Heart Infusion (BHI) broth. Further, the effect of various supplements on antimicrobial activity of bacteriocins against gram-positive bacteria viz., Staphylococcus aureus, Bacillus subtilis and Bacillus cereus and gram-negative bacteria viz., Pseudomonas aeruginosa and Escherichia coli was also evaluated. The results indicate that Lactococcus garvieae yielded high level of bacteriocins 14363.6 AU/ml in M17 medium, where as 11064.5 AU/ml in Soyabean casein digest, 12119.3 AU/ml in BHI, and 13219.0 AU/ml in MRS media at 48 h of incubation. Addition of supplements viz., tween 20, tween 80, amylase, proteinase K and asparginase reduced the antimicrobial activity of bacteriocins.  Whereas Urea, EDTA and NaCl have increased antimicrobial activity of bacteriocins. It is noticed that incubation period of 40, 50 and 60 h, at temperature of 30°C, 40 °C and pH of 6 was found to be an ideal for higher bacteriocins activity. In conclusion, the M17 medium was found to be best for bacteriocins production and the supplements such as Urea, EDTA, and NaCl were found to enhance the antimicrobial activity of bacteriocins. Whereas, pH of 6 was found to be best for bacteriocins production. Therefore, these results are encouraging since the inclination nowadays is to produce large quantities of bacteriocins/probiotics/Antimicrobial peptides (AMPs) which have immense clinical usage in manufacture of alternative types of antibiotics and in various drug preparations.