Killer Yeast汚染清酒もろみの特徴およびKiller Factorの諸性質

概要

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Killer strains for sake yeasts were observed in the wild yeast isolated from koji and mash. During the fermentation process of all batches of main mash (moromi) infected by killer stratins, the following phenomena were observed; 1) In the initial stage of fermentation, decrease of apparaent gravity (Be) was more but production of alcohol less compared with ordinary main mash. 2) Titratable acidity was smaller in the first half of fermentation process but later became larger. 3) Sulphurous order was produced during the initial stage. It was proved that these wild yeast producted a factor having a killer action on sake yeast. The killing activity of that factor produced by a killer strain, No. 78,was inactivated by heating, vigorous agitation and by treatment with proteases. Colls of the sensitive strain were most susceptible to the killing activity of the culture filtrate of the killer strain during their lograthmic growith phase but not in the stationary phase. The accumulation of the killer factor in the culture medium occured most significantly in the medium using peptone, yeast extract, or beef extract as nitrogen source, while not in the medium with ammonium compunds, urea, casamino acid, leucine or glutamic acid. Molecular weight of the killing facotr was estimated as larger than 50,000 by the ultrafiltration method using Diaflo membrane filter.
社団法人日本生物工学会の論文
1974-05-25