BREEDING A FERMENTATIVE YEAST AT HIGH-TEMPERATURE USING PROTOPLAST FUSION

Kluyveromyces marxianus TS87, which was isolated in our laboratory, wa s found to have better growth and fermentative abilities at high tempe rature when compared to the fermentative yeast Saccharomyces cerevisia e TS8. Breeding of K. marxianus TS87 was performed by protoplast fusio n to enhance its fermentation ability at high temperature. During the experiment, 40 fusants were obtained. They were stable during subcultu re and classified into three groups in accordance with the characteris tics of the parental strains. F-1, a fusant of Group 1, was superior t o the parental strains in its high temperature growth and fermentation abilities due to its growth velocity. However, the fusant F-1 lacked the thermostability of S. cerevisiae TS8.