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Saccharomyces yeast spores are more resistant to drying and storage than vegetative cells. For the mass production of yeast spores, compressed yeast was directly inoculated into a sporulation medium (SM). The effects of inoculum size and the addition of rice wine cake (RWC) into SM on the sporulation were examined using flasks. With 1% inoculum of compressed yeast, 1.45×108/ml of asci was obtained. The addition of 0.5% RWC into SM improved the cell growth and spore yield, and the number of asci formed was 2.31×108/ml. The effects of culture temperature, temperatureshift, and concentrations of inoculum, potassium acetate, and RWC on the sporulation were also evaluated using a jar fermentor. The optimum temperature for spore formation was 22oC where the number of asci formed was 2.46×108/ml. The shift of culture temperature from initial 30oC for 1 day to 22oC for 3 days increased the number of asci formed to 2.96×108/ ml. The use of 2% (w/v) inoculum of compressed yeast, 2% potassium acetate, and 1% (w/v) RWC in SM with the shift of culture temperature of initial 30oC to 22oC resulted in 90% sporulation ratio and formation of 6.18×108 asci/ml.
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