ACCUMULATION OF MAGNESIUM-IONS DURING FERMENTATIVE METABOLISM IN SACCHAROMYCES-CEREVISIAE

When cells of Saccharomyces cerevisiae were grown aerobically under gl ucose-repressed conditions, ethanol production displayed a hyperbolic relationship over a limited range of magnesium concentrations up to ar ound 0.5 mM, A similar relationship existed between available Mg2+ and ethanol yield, but over a narrower range of Mg2+ concentrations, Cell ular demand for Mg2+ during fermentation was reflected in the accumula tion patterns of Mg2+ by yeast cells from the growth medium, Entry of cells into the stationary growth phase and the time of maximum ethanol and minimum sugar concentration correlated with a period of maximum M g2+ transport by yeast cells, The timing of Mg2+ transport fluxes by S . cerevisiae is potentially useful when conditioning yeast seed inocul a prior to alcohol fermentations.