TREHALASE. 533 



in species of Penicillium (see p. 363, vol. ii.), is destroyed by a 

 temperature of 63 C. It is, however, doubtful whether the yeast 

 enzyme that decomposes trehalose is identical with this mould- 

 trehalase. 



Bourquelot also found trehalase in barley and green fodder, 

 and pointed out that the enzyme content, also detected in these 

 raw materials by E. FISCHER (XII.), originates in the mould fungi 

 invariably present (see pp. 523, 524, vol. ii.). The French worker 

 even went further, and expressed the opinion that trehalose is 

 probably only fermented by yeasts when the latter have been 

 grown in unsterilised malt worts, and have thus introduced 

 trehalase derived from the raw material. 



According to E. FISCHER (XII.), however, pure yeast will 

 hydrolyse trehalose, though invertase and filtered yeast extract do 

 not. The behaviour of various yeast enzymes towards trehalose 

 was then investigated by A. KALANTHARIANTZ (I.), who found that 

 certain wine yeasts hydrolysed 10-21.5 per cent, of trehalose at 

 22-28 C., bottom-fermentation beer yeasts attacking 10-37.5 per 

 cent, (at 24 C.), top yeasts, including Weissbier and Lichtenhain 

 yeasts, hydrolysing 5-10 per cent., a number of other species 

 7.5-25 per cent., Kissly-Schtschi yeast o and 20 per cent., Logos 

 o on one occasion and 25 per cent, on another, Pombe o on two 

 occasions and 5 per cent. once. These results show considerable 

 irregularity in the progress of hydrolysis, especially with the last- 

 named yeasts. According to DELBRUCK (XIII.), trehalase can 

 be detected in numerous wine, beer, and pressed yeasts. 



The researches of BAU (XVIII.) failed to yield any definite 

 result as to the presence, in bottom yeasts, of an enzyme capable 

 of decomposing trehalose. These experiments were conducted at 

 a fermentation temperature of 2o-25 C., and extended over four 

 months. In the case of most of the organisms examined, the 

 fermentation if occurring at all started slowly and pursued a 

 sluggish course. The trehalose was gradually fermented by the 

 yeasts US, UF, OS, Logos, Sacch. ellipsoideus //., and Saoch. 

 Pastorianus /., II. and III., as well as by Monilia Candida, only 

 an inappreciable alteration of the sugar being produced by a 

 lactose yeast, and very little, if any, by Schizos. Pombe and Sacch. 

 apiculatus. 



According to KAYSER (IV.) the pineapple yeast (see p. 396, 

 vol. ii.) ferments trehalose, the same effect being produced, 

 according to WENT (V.), by Monilia sitophila ; by Allescheria 

 (Eurotiopsis) Gayoni, according to LABORDE (VI.) ; and by the 

 so-called Amylomyccs a and Amylomyces y (see p. 89, vol. ii.), 

 according to ROMMEL and SITNIKOFF (I.). 



LINDNER (XXXIV.) states that trehalose is fermented by a yeast 

 from Kissly-Schtschi, by Monilia Candida and M. . variabilis, by Mucor 

 Rouxii, Amylomyces, by Danzig Jopen yeast No. 602, by a race 

 (No. 402) of Sacch. anomalus, by nearly all the wine yeasts tried, 



