Characterization of bacteriocin producing lactic acid bacteria and its application as a food preservative

Abstract

Lactic acid producing bacteria was isolated from Whey. The isolated strain Lactobacillus fermentum KN02 was potent producer of bacteriocins. Bacterioicin produced by the isolate KN02 had a large spectrum of inhibition against food spoilage microorganisms (Escherchia coli, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis,Pseudomonas aeuroginosa, Klebsiella pneumonia, Bacillus cereus). The bacterioicin inhibited the growth of pathogens but it showed high activity against Bacillus. The bacteriocins were found to be heat stable at 100°C. The maximum antimicrobial activity was retained within the pH range of 2, and completely affected by proteolytic enzyme (papain). Bacteriocins are used to control the frequent development of pathogens and spoiling microorganism in food and feed. Growth of L. fermentum KN02 was inhibited only by few antibiotics suggesting that the strain may be used as a probiotic by the individual receiving medical treatment. The new bacterioicin producing L. fermentum KN02 has been selected for identification and application of bacteriocins to food products (Milk and Mushroom) which reduces the growth of pathogens. The bacteriocins producers L. fermentum KN02 was identified on the basis of phenotypic analysis and 16S rRNA sequences.   Key words: Lactic acid bacteria, Lactobacillus fermentum, bacteriocin, food spoilage microorganisms.