Modulation of the glycerol and ethanol syntheses in the yeast Saccharomyces kudriavzevii differs from that exhibited by Saccharomyces cerevisiae and their hybrid

In the last years there is an increasing demand to produce wines with higher glycerol levels and lower ethanol contents. The production of these compounds by yeasts is influenced by many environmental variables, and could be controlled by the choice of optimized cultivation conditions. The present work studies, in a wine model system, the effects of temperature, pH and sugar concentration on the glycerol and ethanol syntheses by yeasts Saccharomyces cerevisiae T73, the type strain of Saccharomyces kudriavzevii IFO 1802^T, and an interspecific hybrid between both species (W27), which was accomplished by the application of response surface methodology based in a central composite circumscribed design. Results show that carbon flux could be especially directed towards glycerol synthesis instead of ethanol at low pH, high sugar concentrations and low temperatures. In general, the non-wine yeast S. kudriavzevii produced higher glycerol levels and lower ethanol content than wine strains S. cerevisiae T73 and the hybrid W27, with specific and different glycerol production profiles as a function of temperature and pH. These results were congruent with the higher glycerol-3-phosphate dehydrogenase activities estimated for this species, chiefly at low temperatures (14 °C), which could explain why S. kudriavzevii is a cryotolerant yeast compared to S. cerevisiae.