プロトプラスト融合法による高温発酵性醸造用酵母の育種

概要

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To breed a new brewing yeast suitable for high-temperature fermentation, protoplast fusion was done between a sake yeast, Saccharomyces cerevisiae Kyokai no. 7,and a wild yeast, Saccharomyces cerevisiae 1031R-2,which can produce ethanol quickly at 40℃. Five stable fusants were isolated, and physiological studies, showed that two were tetraploid. The ability of fermentation of the fusants at 40℃ were superior to Kyokai no. 7 but inferior to 1031R-2. Kyokai no. 7 produced a weak acid-like off-flavor, and 1031R-2 and the fusants produced it more strongly. Thus strains that produced ethanol quickly with little off-flavor were not found among the fusants.Spores from AM2,one of the tetraploid fusants, were isolated with a micro-manipulator, and their fermentability at 40℃ and production of off-flavor were examined. Of 96 spores isolated, 55 germinated. Kyokai no. 7 had few spores, and the germination of spores from 1031R-2 was lower than that of AM2. The fermentability examination of 55 segregants showed that they produced 2% to 6% ethanol. Ethanol production of two diploid segregants, AM2-17B and AM2-18C, was close to that of 1031R-2,and the off-flavor of the two strains was not strong.The protoplast fusion and segregation method we used was useful for breeding of a new brewing yeast.
社団法人日本生物工学会の論文
1987-01-25