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

Masubuchi, Takashi*; Ueda, Ryoshiro; Kamiyama, Osamu*; Ikenaga, Hiroshi*; Sato, Katsuya; Narumi, Issey*

We have previously obtained high ethyl caproate producing Sake yeasts "No.227" and "No.1333" by ion beam breeding. The fatty acid synthase genes ( and ) and the fatty acid esterase genes ( and ) might be involved in the higher production of ethyl caproate in the mutant strains. In this study, to identify the mutation sites of the mutant strains, each gene locus was sequenced. For the , and loci, all the mutations found in mutant strains are nonsense mutations, suggesting that these mutations did not involved in the higher production of ethyl caproate. On the other hand, strains No.227 and No.1333 carried G/A and A/A mutations in gene at nucleotide position 3,748 as heterozygous and homozygous states, respectively. 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.