Abstract
Lactic acid bacteria, Chizuka, Yasaka 5B,7B,8B, and 9B, which have been previously isolated from different well-aged Nukadoko in the Northern Kyushu area, were investigated for bacteriocin production and purification. Their isolates were shown to produce bacteriocin-like substances. However, the properties of these substances were surprisingly identical to those observed with nisin Z produced by Lactococcus lactis IO-1, previously isolated from kitchen drain of a home in the City of Fukuoka. It was shown in particular that bacteriocins from Lc. lactis IO-1 and the studied isolates displayed the same spectrum of activity with no cross inhibition, identical proteolytic patterns and kinetics of cell destruction, the same retention time in a reversed-phase chromatography and the same UV absorption spectrum. Taking into account the fact that identification of the isolates revealed the same biochemical and genetic patterns as Lc. lactis IO-1, it was therefore concluded that strains Chizuka, Yasaka 5B,7B,8B, and 9B are most likely to be nisin Z producers which could in fact be identical to Lc. lactis IO-1.
