Preliminary Note on the Sake Yeast. 



BY 



K. Yabe, NogakusM'. 



It lias been repeatedly asserted that a fungus related to 

 Aspergillus called Eurotium Oryzce, forms conidia, which can 

 bring on alcoholic fermentation. This fungus plays a great part 

 in the manufacture of sake on account of its high diastatic pro- 

 perties. Rice infected with that fungus, i.e., koji, is mashed 

 along with freshly boiled rice, whereupon, not only sacchari- 

 fication, but also fermentation gradually sets in. Micros- 

 copical examination now reveals the presence of numerous cells 

 of a Saccharomyces, which have the size of the beer yeast, 

 but also frequently are about § larger in diameter. We have 

 made several experiments in this Institute in order to see 

 whether this yeast could be transformed into the above named 

 mycelium fungus, and have always failed, from which it is to be 

 concluded that the sake yeast is not a certain stage of development 

 of Eurotium, but a species quite distinct. We hope to communi- 

 cate at a later occasion the details of further investigations. 

 For the present, the remarks which follow may suffice as to the 

 behaviour of the sake yeast. 



This species exhibits its fermentative activity in solutions 

 containing a much higher percentage of alcohol than certain other 

 kinds of yeasts. A small amount of the yeast was suspended in a 

 Pasteur solution (containing a higher percentage of glucose than 

 usual) and quantities, of 10 cc. each, were placed in seven flasks, 

 to which were added 50 cc. of the Pasteur solution, a measured 

 amount of alcohol of known strength, and the necessary amount 

 of water to make the volume 100 cc. The percentage of sugar 

 in the flasks at the beginning was 9.48. After 6 days the sugar 

 was determined by Allihis method in those bottles where the 

 fermentation had been lively, while in others the usual titration 

 method was used. The results are as follows : — ■ 



