In this study, 22 strains of the budding yeast
Saccharomyces cerevisiae were isolated from several samples obtained from various natural environments in Gifu Prefecture in order to develop novel types of
sake yeast. Among the isolated strains, strains GY38, GY115, GY156, and GY172 were selected for a novel Gifu University
sake yeast strain. By phylogenetic analysis, strain GY115 was classified into the sake yeast group, while strains GY38 and GY156 were classified with baker’s yeast strains. Strains GY38, GY115, and GY172 had comparatively high fermentation abilities at 15ºC, though their abilities were lower than that of strain Kyokai No. 7. These strains showed individual production abilities for organic acids and aromatic compounds:the
sake produced by strain GY115, for example, contained comparatively high levels of ethyl caproate, but the strain could not produce the 4-vinyl guaiacol(4-VG)that results in a phenolic off flavor in
sake. On the other hand, the
sake produced by strain GY38 had a high malic acid/succinic acid ratio(0.77)and low succinic acid concentration. Strain GY115 was able to make
sake on a comparatively large scale fermentation although the
sake contained high concentrations of organic acids, including succinic acid. From these results, it is expected that GY115 has a unique ability to produce specific desirable flavors for
sake production.
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