Summary: Lactose metabolism is an important industrial trait in dairy lactococci. In lactose is taken up via the phosphoenolpyruvate-dependent phosphotransferase system (PEP-PTS) and is subsequently metabolized via the glycolytic and tagatose 6-phosphate pathways. Genes for the lactose-specific PEP-PTS proteins, phospho-β-galactosidase and tagatose 6-phosphate pathway enzymes are encoded by a single 8 kb operon, and there is a divergently transcribed repressor gene. Transcriptional fusions of both the operon promoter and the promoter to the genes of were used to investigate the regulation of expression of both promoters. bioluminescence assays demonstrated that negatively regulates the operon and also autoregulates itself. Induction of transcription occurred for both promoters during growth on lactose: sevenfold for and fivefold for the operon. The promoter was demonstrated to be a particularly strong promoter, being approximately four times more efficient than the operon promoter. Both promoters provide good potential for the inducible expression of foreign proteins in


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