Negatively regulates the transcription of the lutABC operon, which is required for L-lactate utilization. LutR activity is regulated by lactate, since presence of L-lactate, that probably binds to LutR, leads to derepression of the operon. Also appears to be essential for bacilysin biosynthesis. Cells lacking this gene show a derepression of lutABC expression. They are also defective in bacilysin production.