INFLUENCE OF THE PHOSPHORUS AND NITROGEN-SOURCE ON NISIN PRODUCTION IN LACTOCOCCUS-LACTIS SUBSP LACTIS BATCH FERMENTATIONS USING A COMPLEX MEDIUM

The influence of different phosphorus and nitrogen sources on Lactococcus lactis subsp. lactis NIZO 22186 growth and nisin production was studied in batch fermentations using a complex medium. KH2PO4 was found to be the best phosphorus source for nisin production. Increasing initial phosphate concentrations from 0 to 5% KH2PO4 exerted a double effect, creating favourable pH conditions and particularly stimulating the nisin production levels, which were highest at 5% KH2PO4. UP to now, no such high initial phosphate concentrations have been reported for the production of other antibiotics or bacteriocins. Nisin, a lanthionine-containing peptide antibiotic with bacteriocin properties, clearly behaved as a primary metabolite, since its formation was linked with active growth and was not suppressed by phosphate concentrations up to 5%. A complex medium supplemented with cotton seed meal as nitrogen source also gave very high nisin yields.