|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1993 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1992 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1991 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Antibiotic produced by lactic acid bacteria is classified into three groups, nisin produced from Lactococcus lactis, peptide antibiotic produced from Lactobacillus, and peptide produced from pediococcus. Recent year, nisin is regarded as the group of lantibiotic which is defined as the peptide containing abnormal amino acid such as dehydroalanine and lanthionine. Lanthionine has been noticed wiht much attention from the atand point of biochemistry and genetic molecular biology.
Lactococcus lactis IO-1, isolated in our laboratory, produces novel peptide antibiotic which is sensitive to Bacillus subtilis C1, an indicator strain isolated in our laboratory, genus Lactococcus, and genus Lactobacillus. Antimicrobial spectrum of this peptide and other biochemical tests indicated that this peptide is similar to nisin. Peptide was isolated and purified from broth then subjected to amino acid composition analysis, N-terminal amino acid determination, NMR, and FAB-MS.Data showed that the peptide is a nisin derivative in which histidine (27th amino acid from N-terminal) was replaced with aspartate.This has been confirmed by the analysis of nucleotide sequence of the structural nis gene isolated from our strain reported by the research group of Morinaga industry, Co., Ltd. Almost at the same time, MIZO group, the Netherland, reported that the some strains of Lactococcus lactis produce natural variant of nisin, designated nisin Z, which possess same amino acid sequence as our peptide. It is revealed that nisin Z has larger solubility in water than nisin so that nisin Z has advantage over nisin for uses as a food additive.
Peptide antibiotic produced by lactic acid coccus plays an important role for formation of favorable microflora in food processing including fermentation as well as in intestinal tract of human and animal.