ENGINEERING PATHWAYS FOR MALATE DEGRADATION IN SACCHAROMYCES-CEREVISIAE

Deacidification of grape musts is crucial for the production of well-b alanced wines, especially in colder regions of the world. The major ac ids in wine are tartaric and malic acid. Saccharomyces cerevisiae cann ot degrade malic acid efficiently due to the lack of a malate transpor ter and the low substrate affinity of its malic enzyme, We have introd uced efficient pathways for malate degradation in S. cerevisiae by clo ning and expressing the Schizosaccharomyces pombe malate permease (mae 1) gene with either the S. pombe malic enzyme (mae2) or Lactococcus la ctis malolactic (mleS) gene in this yeast, Under aerobic conditions, t he recombinant strain expressing the mae1 and mae2 genes efficiently d egraded 8 g/L of malate in a glycerol-ethanol medium within 7 days. Th e recombinant malolactic strain of S. cerevisiae (mae1 and mleS genes) fermented 4.5 g/L of malate in a synthetic grape must within 4 days.