✍ Scribed by Koppensteiner, G. ;Windisch, S.
No coin nor oath required. For personal study only.
The limit values of osmotic pressure were investigated which ten osmotolerant and two nonosmotolerant yeasts supported in solutions of sugars (fructose, maltose, xylose) and salts (lutrol, sodium chloride, potassium chloride, ammonium chloride, ammonium sulphate and lithium chloride) during fermentation and growth by eryoscopy and isothermal destfllation. Osmotolerant and nonosmotolerant yeasts did not show any different reaction when growing on agar media containing 20/0 resp. 500/0 glucose. The limit values for fermentation of osmotolerant yeasts in fructose solutions were found to be from 238 arm (Saccharomyces rosei) up to 620 atm (S. meUis and S. heterogenicus). The corresponding values of nonosmotolerant yeasts were 160 atm with S. cerevisiae and 124 arm with S. carlsbergensis. The limit values for growth were mostly lower than for fermentation. The highest osmotic values tolerated were found in solutions of fructose. The salt tolerance increased in accordance with the rows of ttofmeister. The low compatibility of concentrated solutions of sodium chloride could be raised by small amounts of fructose. The same effect was caused by lactose and galactose, two sugar types which the yeasts under study do not ferment. Yeast's different tolerance of concentrated solutions of various substances is discussed. The cause is supposed to be a various permeation and a different effect of the dissolved particles on the cytoplasm.
Zusammen/assung. Von 10 osmotoleranten und 2 nichtosmotoleranten Helen wurden die maximal vertr~gliehen osmotischen Werte ffir G~rung und Wachstum in LSsungen yon Fructose, Galactose, Maltose, Xylose, Lutrol, NaC1, KC1, Ammoniumchlorid, Ammonsulfat und Lithiumchlorid kryoskopisch und durch isotherme Dcstillation bestimmt. Sowohl osmotolerante als auch nichtosmotolerante Hefen zeigten im Wachstum auf N~hragar mit 20/0 bzw. 500/o Glucose keinen Unterschied. Die osmotischen Grenzwcrte osmotoleranter Helen ftir die Gi~rung lagen in FructoselSsungen zwischen 238 at (Saccharomyces rosei) und 620 at (S. mellis und S. heterogenicus). Die entsprechenden Wel~e nichtosmotolerant~r Hefen waren 160 at bei S. cerevisiae und 124 at bei S. carlsbergensis. Die Grenzwerte ffir das Wachstum waren racist nicdriger als fiir die G~rung. Alle untersuchten Hefen tolerierten die hSchsten osmotischen Werte in FructoselSsungen. In Neutralsalz-15sungen stieg die Toleranz der Helen entspreehend der ttofmeisterschen Reihe an. Die geringe Vertr~glichkeit konzentrierter Natriumchloridl6sungen kolmte durch
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