Eight yeast strains were isolated from samples collected in Hokkaido after enrichment culture with a high concentration of sucrose. Among them, strain AK 46, which was derived from dough containing fermented cherry fruits was identified as Saccharomyces cerevisiae. The nucleotide sequence of the rDNA spacer region from this strain was identical to those from yeasts used for the production of whisky, wine, and bread. Strain S. cerevisiae AK 46 carried only only SUC2, which is one of multiple genes that encodes invertase, in contrast to the other baking strains, and its sequences were diverged from those of the corresponding gene found in the other strains. In a comparison of six baking strains, strain AK 46 showed lower leavening ability in dough with and without the addition of 5% sucrose by weight of flour but showed high leavening ability in sweet dough containing 30% sucrose. The activities of enzymes α-glucosidase and invertase, which are related to dough fermentation, were lower than those in the other strains. A baking test showed that strain AK 46 was suitable for breadmaking by various methods. Cells of strain AK 46 were propagated industrially and used for the commercial production of dry yeast called “Tokachino”, which is named for the region from which it was isolated.

The yeast strain AK 46 was isolated from dough containing fermented cherry fruits and identified as Saccharomyces cerevisiae. The nucleotide sequence of the rDNA spacer region from this strain coincided with those from the yeasts used for the production of whisky, wine, and bread. In a comparison with six baking strains, strain AK 46 possessed less leavening ability in dough with and without addition of 5% sucrose (based on the weight of flour) but a high ability in sweet dough containing 30% sucrose. The activities of the two enzymes alpha-glucosidase and invertase, which are related to dough fermentation, were lower than those in the other strains. A baking test showed that strain AK 46 was applicable for breadmaking using the straight dough and sponge dough methods. Strain AK 46 carried only SUC2, which is one of multiple genes encoding invertase, in contrast to the other baking strains, and its sequences diverged from those of the corresponding gene from a representative laboratory strain. Southern hybridization of genomic DNA, using the SUC2 gene as the probe, readily discriminated strain AK 46 and other strains. These observations indicate that strain AK 46 is a wild strain possessing breadmaking properties.