Stress effect of ethanol on fermentation kinetics by stationary-phase cells of Saccharomyces cerevisiae

When 4% (v/v) ethanol was added progressively to two strains exhibiting dif ferent fermentative abilities, K1 (a commercial wine strain) and V5 (a stra in derived of a wine yeast), the fermentation rate correlated directly to t he ethanol concentration for both strains. In contrast, the effect of sudde n addition of 2%, 4% or 6% (v/v) ethanol was different depending on the str ain. While the same effect was observed for K1 whatever the way of ethanol addition, V5 required an adaptation period after the shock addition of etha nol.