Growth and physiological properties of different-ploided fusants of Saccharomyces cerevisiae and Saccharomyces diastaticus

Tested strains are different- ploided fusants of S. cerevisiae strain HU-TY-1A and S. diastaticus strain 5206-1B by means of protoplast fusion. Comparative studies of growth rate and biomass, osmotic pressure and alcohol tolerance, and fermentation ability between the fusants and the parental strains showed that the fusants were quitely different from parental strains HU-TY-1A and 5206-1B; while two fusants, 4AB2-60 and 4BA1-3 which were both 4n, were found to be prominent in physiological properties. They were both thermotolerant, resistant to high osmotic pressure, alcohol-tolerant, and better at fermenting starch and glucose than their parents, especially at 40°C. It was also found that there existed a gene-dosage effect with single-parental fusants.