Genome analysis of high ethyl caproate producing sake yeasts generated by ion beam breeding

Masubuchi, Takashi*; Hyuga, Hirokazu*; Ueda, Ryoshiro; Hayashi, Hidenori*; Ikenaga, Hiroshi*; Sato, Katsuya; Ono, Yutaka

We analyzed genome sequence of the high ethyl caproate producing sake yeast mutant (No.227) generated by ion beam breeding in order to investigated factors contributing the reduced ability to alcohol fermentation. In the high ethyl caproate producing sake yeast, four pyruvate decarboxylase genes (PDC), six alcohol dehydrogenase genes (ADH), two biotin synthesis genes (BIO) and chitinase gene (CTS1) might be involved in the reduced ability to alcohol fermentation. The genome sequence of the strain No.227 was determined by a whole-genome shotgun strategy using pyrosequencing method and compared with the whole-genome sequence of the sake yeast strain Kyokai 7, which is characterized by the fermentation property, as a reference sequence. For the PDC, ADH, BIO and CTS1 loci, no mutation was found in the strain No.227, suggesting that these genes did not involved in the reduced ability to alcohol fermentation.