ISOLATION AND CHARACTERIZATION OF BACTERIOCIN PRODUCING LACTIC ACID BACTERIA FROM A SOUTH INDIAN SPECIAL DOSA (APPAM) BATTER

Lactic acid bacteria (LAB) commonly used as starter cultures in food are known to produce antimicrobial substances such as bacteriocins, having great potential as food biopreservatives. The present study was aimed at isolating bacteriocinogenic LAB from a traditional fermented food, "Appam". Twenty five colonies of LAB were isolated and screened for bacteriocin production potential. Ten isolates showed good antimicrobial activity against Gram-positive viz.,Bacillus cereus , Staphylococcus aureus , Listeria monocytogenes as well as Gram-negative viz., Pseudomonas aeruginosa , Vibrio parahaemolyticus and Aeromonas hydrophila microorganisms. During characterization of these strains two of them were found to resemble two other strains. One of the bacilli has been reported earlier. Therefore, in this study characterization of 7 isolates through morphological, physiological, biochemical and carbohydrate fermentation tests as well as cell wall protein profiles have been reported. Five of them were cocci, identified as Pediococcus pentosaceous (4 strains) and the other as Tetragenococcus halophilus, while the remaining two being rods and were found to be Lactobacillus plantarum.