Vacuolar H⁺-ATPase Protects Saccharomyces cerevisiae Cells against Ethanol-Induced Oxidative and Cell Wall Stresses

Abstract

The yeast Saccharomyces cerevisiae has been widely used in the alcoholic fermentation industry. Among the environmental stresses that yeast cells encounter during the process of alcoholic fermentation, ethanol is a major stress factor that inhibits yeast growth and viability, eventually leading to fermentation arrest. This study provides evidence for the molecular mechanisms of ethanol tolerance, which is a desirable characteristic for yeast strains used in alcoholic fermentation. The results revealed that straight-chain alcohols induced cytosolic and vacuolar acidification through their membrane-permeabilizing effects. Contrary to expectations, a role for V-ATPase in the regulation of the cell wall stress response and the prevention of endogenous oxidative stress, but not in the maintenance of intracellular pH, seems to be important for protecting yeast cells against ethanol stress. These findings will expand our understanding of the mechanisms of ethanol tolerance and provide promising clues for the development of ethanol-tolerant yeast strains.