Production of Bacteriocin Like Substances as Antipathogenic Metabolites by Bacillus licheniformis Isolated from Healthy Human Skin

Different types of bacterial colony were isolated from skin of 30 healthy human and their antipathogenic activity was tested against 9 pathogens. The isolate showed activity against pathogen- Kl. pneumoniae subsp. pneumoniae, was identified as Bacillus licheniformis Variation was found in optimization of cultural conditions (incubation period, incubation temperature and pH) for the most potent antipathogenic metabolites production. Bacillus licheniformis showed most potent antipathogenic activity at pH 7, at an incubation period of 48h and at an incubation temperature of 250C. Antipathogenic metabolites was then detected as bacteriocin like substances. Samples containing bacteriocin like substances were characterized with respect to their heat and pH stability and susceptibility to denaturation by the enzyme. It showed heat stability up to 800C for 30 minutes, stability up to pH 7. Papain treated cell-free supernatant did not show any bacteriocin activity, suggesting that the substances could be antimicrobial peptides. Solvent extraction of bacteriocin was performed by using chloroform and here maximum bacteriocin activity was found in interface layer rather than aqueous and organic layer