Abstract: This work is to explore the metabolic mechanism of Saccharomyces cerevisiae and the change of the cell membrane function while adding different concentrations of Ca2+ under different pH. Using S. cerevisiae as research target，the metabolic characteristics of yeast cells were studied by adjusting pH and the concentration of Ca2+ in model grape juice medium，and also the metabolic mechanisms were investigated from the perspective of permeability and integrity of the cell membrane. The fermentation was conducted under the condition of temperature was 28℃，rotation speed was 120 r/min，and inoculation was 1×106 mol/L. Results showed that the rate of metabolism was accelerated，and the permeability and integrity of cell membrane were enhanced with the increase of Ca2+ concentration when the pH was 3.0，indicating that the inhibiting effect caused by low pH was eliminated after adding Ca2+. The effect of Ca2+ addition was not significant when the pH was 5.5. The above results indicated that Ca2+ alleviated the physiologically toxic effects of low pH on S. cerevisiae.

Key words: yeast, Ca2+, pH, metabolism, cell membrane