Malo-ethanolic fermentation in grape must by recombinant strains of Saccharomyces cerevisiae

Recombinant strains of Saccharomyces cerevisiae with the ability to reduce wine acidity could have a significant influence on the future production of quality wines, especially in cool climate regions, L-Malic acid and L-tartaric acid contribute largely to the acid content of grapes and wine. The mine yeast S. cerevisiae is unable to effectively degrade L-malic acid, whereas the fission yeast Schizosaccharomyces pombe efficiently degrades high concentrations of L-malic acid by means of a malo-ethanolic fermentation, However, strains of Sz. pombe are not suitable for vinification due to the production of undesirable off-flavours, Heterologous expression of the Sz. pombe malate permease (mae1) and malic enzyme (mae2) genes on plasmids in S. cerevisiae resulted in a recombinant strain of S. cerevisiae that efficiently degraded up to 8 g/l L-malic acid in synthetic grape must and 6.75 gn L-malic acid in Chardonnay grape must, Furthermore, a strain of S, cerevisiae containing the mae1 and mae2 genes integrated in the genome efficiently degraded 5 g/l of L-malic acid in synthetic and Chenin Blanc grape musts. Furthermore, the male-alcoholic strains produced higher levels of ethanol during fermentation, which is important for the production of distilled beverages, Copyright (C) 2001 John Wiley & Sons, Ltd.