CLONING, SEQUENCE AND EXPRESSION OF THE GENE ENCODING THE MALOLACTIC ENZYME FROM LACTOCOCCUS-LACTIS

Many lactic acid bacteria can carry out malolactic fermentation. This secondary fermentation is mediated by the NAD- and Mn2+-dependent malo lactic enzyme, which catalyses the decarboxylation Of L-malate to L-la ctate. The gene we call mleS, coding for malolactic enzyme, was isolat ed from Lactococcus lactis. The mleS gene consists of one open reading frame capable of coding for a protein with a calculated molecular mas s of 59 kDa. The amino acid sequence of the predicted MleS gene produc t is homologous to the sequences of different malic enzymes. Bacterial and yeast cells expressing the malolactic gene convert L-malate to L- lactate.