Production and Screening of Bacteriocin with a Broad Antimicrobila Spectrum of Lactobacillus

The main purpose of these works is to reveal antimicrobial activity of bacteriocin produced by Lactobacillus species. It has large spectrum of inhibition against photogenic food spoilage microorganisms etc., Lactobacilli are important organisms recognized for their fermentative ability as well as their health and nutritional benefits. They produce various compounds such as organic acids, diacetyl, hydrogen peroxide and bacteriocin or bactericidal protein during lactic fermentation. Lactobacilli was cultured in MRS broth and incubated for 24 hrs. After incubation the broth was centrifuged and supernatant was collected. The antimicrobial activity of the bacteriocin was assayed by agar spot test using gram positive and gram negative bacteria. The thermo stability of the antibacterial activity was determined and assayed for bacteriocin. The antimicrobial substance produced by the strain was thermo resistant for 30min at 100°C. Maximum activity in composed medium was achieved at initial pH of 5.5 and incubation period of 48hrs at 30-37°C. The supernatant was subjected to UV treatment by exposing the supernatant to UV light. Plasmid was isolated using STE buffer and no plasmids were suggesting that the genes encoding bacteriocin production were located on the genome.