Improving nisin production by increasing nisin immunity/resistance genes in the producer organism Lactococcus lactis.

摘要

The effect of increasing nisin immunity/resistance genes in Lactococcus lactis subsp. lactis MG1363 on nisin production was investigated. The 60-kb nisin immunity/resistance plasmid pND300, which was isolated from a non-nisin-producing strain, encoded 5 genes involved in nisin immunity/resistance, which were very similar to those of the immunity/resistance system encoded by the nisin-production transposon. The introduction of pND300 into MG1363(TnNip) caused the construct to produce significantly more nisin than the parent MG1363(TnNip). The introduction of pND314, which contained the nisin immunity/resistance genes subcloned into pSA3, into MG1363(TnNip) allowed the strain to grow more rapidly than the parent MG1363(TnNip) with a concomitant increase in the rate of nisin production. It is suggested that the introduction of pND300 and a derivative containing the nisin immunity/resistance system of pND300 into MG1363 (TnNip) could modify the kinetics of nisin production. The use of this approach could improve the rate and concentration of nisin production.