Identification of mutation sites in high ethyl caproate producing sake yeasts generated by ion beam breeding

Masubuchi, Takashi*; Takashima, Chisato*; Kamiyama, Osamu*; Ikenaga, Hiroshi*; Sato, Katsuya; Narumi, Issei

In the previous study, we have obtained high ethyl caproate producing Sake yeasts No.227 and No.1333 by carbon-ion irradiation. In this study, to identify the mutation sites of the mutant strains, the specific region (226 bp; nucleotide positions 3,642-3,867) in the fatty acid synthase gene that might be involved in the higher production of ethyl caproate was sequenced and compared with the corresponding sequence in the parental strain Kyokai-901. Consequently, strains No.227 and No.1333 carried G/A and A/C mutations, respectively, at nucleotide position 3,748 as a heterozygous state. This result strongly suggested that the higher production of ethyl caproate in strains No.227 and No.1333 is attributed to a dominant mutation in gene.