Cloning and characterization of mersacidin like bacteriocin from Bacillus licheniformis MKU3 in Escherichia coli.

A putative gene encoding mersacidin like lantibiotic bacteriocin (lanA) was identified in Bacillus licheniformis genome. The lanA open reading frame codes for 74 amino acids with calculated isoelectric point of 6.7 and molecular mass of 8.2 kDa. The lanA gene was amplified from B. licheniformis MKU3, cloned in pQE30 vector and overexpressed in Escherichia coli M15. The recombinant peptide was purified to homogeneity using Ni-NTA chromatography and the SDS-PAGE analysis of the purified peptide revealed it to be a monomer with molecular mass of ~8.5 kDa. The purified bacteriocin showed wide spectrum activity against gram-positive pathogens. The peptide was found to be stable under in wide range of pH, temperature tolerant and resistant to the proteolytic enzymes. The stable nature of the bacteriocin to high temperature and resistant to various chemicals it also exhibited antimicrobial activity against food-borne pathogens make this bacteriocin as potent attractive antimicrobial agent in food products.