Enhancing ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae by Mg2+ via reduction in plasma membrane permeability.

Mg2+ at 3.5 mM increased the tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae to ethanol. After 9 h of exposure to 20% (v/v) ethanol at 30 degrees C, all cells died whereas over 50% remained viable for the cells grown with Mg2+. The effect of Mg2+ is closely related to its ability to decrease plasma membrane permeability of cells subjected to ethanol stress.