Detection and Characterization of A Heat Stable Bacteriocin (Lactocin Lc-09) Produced by A Clinical Isolate of Lactobacilli

A new bacteriocin lactocin LC-09 produced by Lactobacillus strain LC-09, isolated from a clinical sample, was inhibitory against many species of lactobacilli and other Gram-positive bacteria including Listeria ivanovii, Streptococcus agalactii and S. peyogenes. Characterization of the bacteriocin revealed it to be extremely heat stable (4 hours at 100°C) and active at acidic pH values. This bacteriocin was inactivated by protease treatment. Curing of LC-09 with acridine orange, ethidium bromide and by elevated temperature (40°C) resulted in mutants defective in bacteriocin production.