As a primary study for cell growth and alcohol production of a cider yeast, Saccharomyces sp. R-11, cultural and nutritional characteristics of the strain were investigated. The results obtained were as follows:
The optimum culture medium for this strain was a synthetic medium, Henneberg B, and sucrose was the best carbon source for yeast growth and alcohol production. Optimum sugar concentrations for yeast growth and alcohol production were 15% and 25%, respectively. Optimum pH and temperature of the basal medium for growth of this strain were 4.5 and 30℃, respectively. The yeast growth was enhanced by the addition of 100 ppm of Mg^(2+), but significantly inhibited by the addition of 100 ppm of Co^(2+). bower temperature and maintenance of optimum pH for yeast growth increased the final alcohol concentration. Under optimum condition for cell growth at stationary culture, generation time and specific growth rate of the strain were 7.5 hr and 0.092 hr^(-1), respectively. At 8% initial alcohol concentration, yeast growth was inhibited about 509b and this strain could not be grown at more than 12% initial alcohol. The strain could be grown at less than 125ppm SO₂ without alcohol addition, and at less than 75 ppm SO₂ with 8% initial alcohol. The higher sulfur dioxide concentration of a medium, the longer lag phase in yeast growth was observed. This strain could induced alcoholic fermentation at less than 10% initial alcohol concentration with 0 and 25 ppm SO₂, at less than 8% initial alcohol with 50 and 75 ppm SO₂, and at less than 6% initial alcohol with 100 and 125 ppm SO₂.
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