Host specificity of nisin production by Lactococcus lactis

Kinetics of nisin production have been investigated in terms of endogenous features of the producer organism, Lactococcus lactis. Nisin-producing transposons (Tn Nip) were transferred to different hosts by conjugation. Constructs were cultivated in batch cultures and nisin produced was measured. The proteinase function of C2Prt (Tn Nip)-1 was eliminated by plasmid curing, resulting in the construct C2Prt - (Tn Nip)-1. C2Prt - (Tn Nip)-1 produced nisin to a higher concentration compared to C2Prt (Tn Nip)-1 and was able to maintain the maximum concentration till the end of cultivation. The final concentration of nisin produced was host-specific, because when different constructs carrying the same Tn Nip were cultivated they produced nisin to different concentrations. However, when the same host carried Tn Nip transposons derived from different donors the concentration of nisin produced was similar, suggesting that the two Tn Nip transposons may be similar.