Cciv. Studies on Yeast Grown

IN the previous communication [Pett, 1935, 3] the observation was reported that yeast could be grown in media containing cyanide. The resulting yeast was found to have a high fermentative capacity, and a respiration largely insensitive to cyanide. It contained several times the normal content of flavin, in the form of flavoprotein. The present communication gives a comparison of cyanide-yeast with yeast experimentally grown aerobically (like baker's yeast), and anaerobically (like bottom yeast), together with observations on the effect of prolonged subculture in cyanide. The results show definite differences in the three classes of yeast; prolonged subculturing in cyanide resulted in the disappearance of flavin from extracts of the yeast, with the appearance of a blue fluorescence. Some of the properties of this yeast are given.