Factors Affecting Sugar Utilization and Rate of Fermentation During Vinification

Adenine supplementation stimulated fermentation rate in Montrachet at low (15°C) temperature by reducing the lag time to onset of fermentation, and by shortening the time to dryness. There appeared to be little impact on maximum fermentation rate. Prise de Mousse and Pasteur champagne were unresponsive to adenine supplementation. The effect of adenine was greatest at an intermediate concentration and not affected by nitrogen supplementation. Thus, the stimulation appears to be adenine-specific, not a simple consequence of the presence of extra nitrogen. Loss of two glucose transporter proteins SNF3 and HXT2, reduced rate of fermentation at the end of fermentation. The HXT1 glucose transporter does not play a major role during vinifcation. Interestingly, fermentations conducted by mutants lacking HXT2 were always over run with bacteria. Loss of this gene affected competitiveness of this yeast strain.