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-tart aric acid contribute largely to the acid content of grapes and wine. The mi ne yeast S. cerevisiae is unable to effectively degrade L-malic acid, where as the fission yeast Schizosaccharomyces pombe efficiently degrades high co ncentrations of L-malic acid by means of a malo-ethanolic fermentation, How ever, strains of Sz. pombe are not suitable for vinification due to the pro duction of undesirable off-flavours, Heterologous expression of the Sz. pom be malate permease (mae1) and malic enzyme (mae2) genes on plasmids in S. c erevisiae resulted in a recombinant strain of S. cerevisiae that efficientl y degraded up to 8 g/l L-malic acid in synthetic grape must and 6.75 gn L-m alic acid in Chardonnay grape must, Furthermore, a strain of S, cerevisiae containing the mae1 and mae2 genes integrated in the genome efficiently deg raded 5 g/l of L-malic acid in synthetic and Chenin Blanc grape musts. Furt hermore, the male-alcoholic strains produced higher levels of ethanol durin g fermentation, which is important for the production of distilled beverage s, Copyright (C) 2001 John Wiley & Sons, Ltd.