Purification and Characterization of a Novel Broad-spectrum Bacteriocin from Bacillus licheniformis MKU3

A bacterial strain Bacillus licheniformis MKU3, isolated from slaughterhouse sediments showed a strong antimicrobial activity. The antimicrobial substance produced by this strain was found to be a protein that inhibited a broad range of bacterial strains, such as Bacillus sp., Staphylococcus sp., Streptococcus sp., and Listeria monocylogenes. The antimicrobial peptide was purified to homogeneity by cut off membrane filtration followed by gel filtration chromatography. The purified protein with low molecular mass (< 8 kDa) was resolved as single band on Tricine SDS-PAGE. This protein was stable at 100 degrees C for 10 min, but lost its activity at 121 degrees C in 15 min. It was resistant to the proteolytic action of trypsin, proteinase K, and pronase E and stable within a wide range of pH (3.0 similar to 11.0). This protein exhibited lytic activity on selected indicator strain Kurthia gibsonii GCS6.