Effects of Temperature, pH, and Sugar Concentration on the Growth Rates and Cell Biomass of Wine Yeasts

Twenty two strains of wine yeasts representing species of <i>Kloeckera apiculata, Torulaspora delbrueckii, Pichia anomala</i>, various <i>Candida</i> species, and <i>Saccharomyces cerevisiae</i> were examined for growth rates and maximum cell biomass during fermentation of a chemically defined grape juice medium at 10°C, 15°C, 20°C, and 25°C. Growth rates for all species increased with temperature. For most strains, maximum cell biomass increased until 15°C, after which no change, decrease or increase occurred, depending on strain. Several strains of <i>Kl. apiculata</i> as well as some strains of <i>C. pulcherrima, C. stellata</i> and <i>C. colliculosa</i> could grow faster than <i>S. cerevisiae</i>, thereby explaining their early development in wine fermentations. Variation of medium pH between 3.0 and 4.0 did not significantly affect the growth rate or cell biomass of the yeasts. Increasing the sugar concentration of the juice from 200 g/L to 300 g/L gave decreased growth rates for some yeasts and, for all yeasts, final cell biomass was decreased.