Abstract: A brewing yeast mutant with perfect maltotriose fermentation capacity was obtained by mutagenizing the wild yeast Saccharomyces cerevise.The mutant is able to utilize maltotriose efficiently,and the maltotriose fermentability in YNB-2% maltotriose medium increases from 32.4% to 81.8% after 5 d by shaking culture.The TLC pattern showed that the maltotriose transport ability of the mutant is higher compared with the original strain.The wort fermentation test confirmed that the sugar fermentation property of the mutant is superior to the original strain,while the primitive fermentation characters are kept.Therefore,the brewing yeast mutant would benefit the beer industry and be suitable for low caloric beer production.

Key words: maltotriose, mutagenesis, beer, Saccharomyces cerevise