CITRATE PERMEASE GENE-EXPRESSION IN LACTOCOCCUS-LACTIS SUBSP LACTIS STRAINS IL1403 AND MG1363

Citrate permease gene expression in the plasmid-free Lactococcus lacti s strains IL1403 and MG1363 was studied. The ability to transport citr ate results in diacetyl and acetoin production in IL1403 but not in MG 1363. Citrate lyase, alpha-acetolactate decarboxylase, diacetyl and ac etoin reductase were detected in IL1403. These data show that L. lacti s ssp. lactis strain IL1403 is a citrate permease mutant of the biovar . diacetylactis. Immunological analysis revealed the alpha- and beta-s ubunits of citrate lyase not only in IL1403 but also in MG1363 where n o citrate lyase activity was found.