Ion beam breeding of "sake yeast" and test brewing, 2

Masubuchi, Takashi*; Kamiyama, Osamu*; Sato, Katsuya; Hase, Yoshihiro; Narumi, Issei

We are trying to obtain high ethyl caproate producing sake yeast by carbon-ion irradiation. Freeze-dried yeast was irradiated with 220 MeV carbon ion beams in a range of dose from 50 to 300 Gy by AVF cyclotron at JAEA. We isolated 1,135 cerulenin resistant mutants of sake yeast "Kyokai-901" and "No.227 (previously generated ion beam mutant strain)". A 57 kg-scale test brewing demonstrated that No.227 has enough fermentation ability like KAZE-2, and further suggested that No.227 is suitable for practical use as a new type of yeast for quality sake because of its sweetness and uniqueness in flavor.