METHODS FOR SPORULATION OF INDUSTRIALLY USED SAKE YEASTS

Industrially used sake yeasts (Saccharomyces cerevisiae) such as Kyoka i no. 7 and no. 9 hardly sporulate under any of the nutritional condit ions examined to date. However, through acquisition of either sensitiv ity to ethionine or the ability to grow at 35 degrees C in the presenc e of beta-alanine, these sake yeasts were found to regain the ability to form asci with 4 viable spores at high frequency. These methods for the mutant-selection may facilitate the genetics of industrially used yeasts and their breeding by hybridization.