Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : food pathogens


Isolation and Characterization of Nisin-Like Peptide Produced by Lactococcuslactis Isolated from Indian Curd

Saba A. Mahdy; P.T. Kalaichelvan

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 298-309

Twenty isolates of lactic acid bacteria (LAB) from traditional dairy Indian curd were tested for sugar fermentation test, strains were preliminarily identified as Lactococcuslactis sp. lactis by physiological and biochemical test. The identification by PCR analysis and partial 16S rRNA confirmed that N5 were 100% identical to Lactococcus. lactissp. lactis. The results revealed that only the bacteriocin produced from strain N5 was shown as being active against mostly gram positive bacterial indicators. The bacteriocin produced also exhibited a strong inhibitory effect on the foodborn pathogen, Staphylococcus aureus, which is mostly reported as the dominant foodborn pathogen in foods. This bacteriocin producing LAB The bacteriocin has a broad antibacterial spectrum similar to that of nisin and inhibited several related species of lactic acid bacteria and other Gram-positive bacteria. The inhibitory activity of the bacteriocin was found to be stable over a wide range of pH and temperature. The molecular weight of the peptide was judged to be 3.5 kDa by SDS-polyacrylamide gel electrophoresis. These results indicate that bacteriocin produced by L. lactis sp. lactis N5 is a nisin-like bacteriocin.