Studies on the Mode of Action of Bacteriocin Produced by Lactobacillus fermentum CrT21

Lactic acid bacteria (LAB) are very important preservative microflora involved in the fermentation of food products due to their ability to produce organic acids, bacteriocins and other bioactive antimicrobial metabolites. LAB in this study were isolated from cassava waste and retting, screened for their ability to produce bacteriocin and the bacteriocin was subsequently characterized. Lactobacillus fermentum CrT21 produced bacteriocin with crude and purified activity units of 1280 and 2560 AU/ml respectively, purification was done by ammonium sulphate precipitation and through 1, 10 and 20 KDa ultrafiltration membranes. The bacteriocin retained its inhibitory activity over a wide range of temperature (400-1000C), pH (2-10) and in presence of metals, surfactants and enzymes (lipase and lysozyme), the activity was further characterized to cleave the peptide bond between D-glutamic acid and L-lysin along the peptide stem chain of L. fermentum CpL08 peptidoglycan wall.