@article{oai:repo.qst.go.jp:00082301,
 author = {Watanabe, Takashi and Yanagisawa, Masaomi and Katsuya, Sato and Yutaka, Ono and Katsuya, Sato and Yutaka, Ono},
 journal = {QST Takasaki Annual Report 2019},
 month = {Mar},
 note = {Japanese sake, called as “koku-syu” is a traditional liquor of Japan. It is made from steamed-rice, koji-rice, and water. The various characters of Japanese sake such as sweetness/dryness, rich/light, acidity, and ginjyo-aroma vary depending on sake yeasts. Therefore, various sake yeasts are isolated and bred at each region of Japan. Our group have succeeded in breeding and practical utilization of sake yeast Saccharomyces cerevisiae No. 227 by ion-beam mutagenesis for the first time in the world. Moreover, we also bred non-urea producing Gunma KAZE2 yeast (KAZE2-Arg) which is suitable for export by ion-beam irradiation. However, the viabilities of sake yeasts prepared for ion-beam mutagenesis were under 0.1%. Thus, it was considered that some mutagenesis stress was provided for yeast cells before ion-beam irradiation. Therefore, some improvement trials are needed for evaluating superiority of ion-beam breeding methods. In this study, we investigated conditions to prepare yeast cells for ion-beam mutagenesis. Consequently, improved conditions were follows. Yeast cells were cultivated in YPDS medium with shaking at 150 rpm, 30 °C for 24 h. Cells were harvested and washed with sterilized saline (0.9% NaCl) and adhered on cellulose acetate membrane (0.22 µm). After air-dried treatment, 20 ml YPD medium was added on the membrane and incubated at room temperature for 1-2 h. Yeast viabilities were reached at 90%.},
 pages = {98--98},
 title = {Development of Sake Yeasts Preparation Method with Improved Viability for Ion-Beam Mutagenesis},
 volume = {QST-M-29},
 year = {2021}
}