Abstract

A novel bacteriocin Toebicin 218 was isolated from Geobacillus toebii HBB-218, a soil inhabiting Gram positive bacterium. The cell free culture supernatants of G. toebii HBB-218 showed antibacterial activity against many Gram positive bacteria including thermophilic strains. Purification of the bacteriocin was achieved after ammonium sulphate precipitation, gel filtration and ion exchange chromatography. Tricine-SDS-PAGE yielded a single protein band observed with a molecular mass of 5.5 kDa. The antibacterial compound was heat stable and sensitive to proteolytic enzymes. Bacteriocin production started at the early logarithmic phase and maximum production was observed at the end of the stationary phase. Bacteriocin was found to be effective especially against thermophilic bacteria and it may have a potential for use as a biopreservative in canned foods. This study provides the first data on bacteriocin produced by a strain of G. toebii.

Key words: bacteriocin, Geobacillus toebii, toebicin 218, thermophilic, characterization.