Nisin Z produced by Lactococcus lactis subsp. lactis SBT 1212 and comparison of antibacterial activity with Nisin A

Twenty-five lactococcal strains isolated from milk and fermented milk products were tested for bacteriocin production. Lactococcus lactis subsp. lactis SBT 1212 was the only strain producing nisin analogue which was classified to be nisin Z by chemical characterization and PCR amplification of structural genes. Antibacterial activities of nisin A (commercial product) and nisin Z (SBT 1212) against food-born pathogenic bacteria (gram-positive 10 and negative 6) were compared. The growth of Bacillus cereus JCM 2152, IFO 13494, IFO 13690, and Salmonella enteritidis IFO 3313 was more inhibited by nisin Z than by nisin A. To our knowledge, this is the first finding of the different activities of nisin A and Z.