Screening, Identification and Characterisation of Bacteriocins Isolated from Wine Microflora
Bacteriocins are antibacterial proteins produced by bacteria that can kill or inhibit the growth of other bacteria. Many lactic acid bacteria produce a high diversity of different bacteriocinsThe project aims at isolation, partial purification and characterization of bacteriocins from fermented beverages (wine).Fermented wines of grapes, gooseberry and pineapple were sources for isolation of bacteriocinogenic strains.Test organism employed were the major food borne pathogen, Listeria monocytogenes (MTCC 657 The results were confirmed by the loss in cell viability of the indicator observed by performing cell viability test . Well diffusion assay with the partially purified bacteriocin confirmed the inhibitory activity of the bacteriocin against the test organisms. As for the effect of temperature, the PPB was found to be stable at all temperatures upto 110°C. The effect of pH on the bacteriocin activity was checked and it was found that maximum activity was observed at (10,000 AU/mL) at pH 2 for Lactobacillus sp where as for Bacillus sp maximum activity was observed at (1000 AU/ml) at pH 8. Thus optimal production of the bacteriocin isolated from Lactobacillus sp was found to be maximum at pH 2 and that of Bacillus species was maximum at pH 8 . Proteinaceous nature of the antibacterial peptide was confirmed by treating the supernatant solution with Proteinase K enzyme (1mg/ml) which indicated the inhibition of bacteriocin activity. Molecular size of the preteinacaeous compound from Bacillus sp was estimated to be 25 kDa from which provides the inference that they may belong to class III bacteriocins. Overlaying of indicator strain over the isolated protein bands confirmed the inhibitory property of the isolated peptide fragment. Further purification and charecterisation of the peptides will provide an insight on their inhibitory characteristics.