Detection and partial characterization of bacteriocin produced by Leuconostoc isolated from Thai fermented food

Abstract

            Lactic acid bacteria isolated from various Thai fermented foods were tested for bacteriocin activity. One isolate of the lactic acid bacteria, designated as Leuconostoc mesenteroides TFF5, was shown to produce an antimicrobial substance that had characteristics of a bacteriocin. The bacteriocin produced by L. mesenteroides TFF5 was heat stable, retained activity after heating at 100oC for 30 min and at 121oC for 15 min and stable at pH values ranging from 2 to 10. The bacteriocin was sensitive to all proteolytic enzymes used in this study, but resistant to non-proteolytic enzymes. Inhibitory activity of the bacteriocin was limited to the gram-positive indicator bacteria tested. It exhibited bacteriocidal effect without cell lysis against sensitive cells. Bacteriocin activity was detected initially in log phase of culture growth and its maximal activity coincided with the onset of stationary phase. L. mesenteroides TFF5 was shown to contain no plasmids suggesting that genetic determinant for bacteriocin production was likely to be chromosomal encoded.