清酒酵母協会7号の温度感受性自己消化変異株の分離

概要

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Temperature-sensitive autolysis mutants were isolated from a sake yeast, strain (Kyokai No.7) of Saccharomyces cerevisiae, which is thought to be diploid. Isolation was performed by positive selection using a medium on which 2-deoxy-galactose-resistant mutants were able to grow. Yeast cells (1×10^8) were spread on a 2-deoxy-galactose plate, and about 100 colonies were isolated after incubation for 5d at 25℃. About 1% of the mutants from the isolated colonies were deficient in assimilating galactose, and these included temperature-sensitive autolysis mutants at a high frequency (about 50%). In test brewing of sake, one isolate, strain gal-31,had the same fermentation activity as Kyokai No.7,and the sake produced from gal-31 had a satisfactory quality when compared with that made from Kyokai No.7. The resultant sake cake was stored at 37℃ to determine the concentrations of alkaline phosphatase and S-adenosylmethionine, which were used to indicate the extent of yeast cell autolysis. The concentrations in the sake cake from strain gal-31 increased rapidly on storage at 37℃, supposedly because autolysis in the mutant cells in the cake was progressing. These results supported the probability that storing sake cake made from temperature-sensitive autolysis mutants at a higher non-permissive temperature has a positive effect on the ripeness.
社団法人日本生物工学会の論文
1995-05-25