Isolation and Characterization of the Lactic Acid Bacterial Strain GM005 Producing a Antibacterial Substance from Miso-Paste Product

Abstract

A total of 125 strains of lactic acid bacteria were isolated from Miso-paste products made in Yamanashi prefecture, Japan and tested for bacteriocin production by modified agar well diffusion method. Only one isolate designated as GM005 showed antibacterial activity against Bacillus subtilis JCM1465T and Staphylococcus aureus JCM12544T. This suggested that the antibacterial substance produced by strain GM005 could be of a proteinaceous nature and that the antibacterial action was a bacteriocin. The bacteriocin was stable even after autoclaving at 121°C for 15 min in the pH range of 3 to 7, and showed a broad antibacterial spectrum among tested lactic acid bacteria. Strain GM005 was identified as a lactic acid bacterium belonging to the genus Enterococcus. This is the first report dealing with a bacteriocin produced by lactic acid bacteria isolated from Miso-paste.