Detection of nisin expression by Lactococcus lactis using two susceptible bacteria to associate the effects of nisin with EDTA.

Nisin, a bacteriocin produced during the exponential growth phase of Lactococcus lactis ATCC 11454, inhibits the growth of a broad range of Gram-positive bacteria. Gram-negative bacteria can also be inhibited by nisin with EDTA. In this study, nisin production was assayed by the agar diffusion method using Lactobacillus sake ATCC 15521 and a recombinant Escherichia coli DH5-alpha expressing the recombinant green fluorescent protein as the nisin-susceptible test organisms.