Comparative studies on “Saké yeast”, isolated from two different type of “Shubo” mash by differential centrifugation

Abstract

From the standpoint of ecological microbiology, it is interesting to know what physiological characters the yeast, grown in the typical different Sake-brewing prosess, has
In this paper, by using the yeasts isolated from Sokujo-moto and Yamahai-moto mashes by differential centrifugation, characters of the each yeast were compared, and the following results were obtained.
The growth of Yamahai-moto yeast was more markedly retarded than that of Sokujo-moto yeast by the addition of 10 % ethanol and 1 or 2 % lactic acid in synthetic and koji-extract media.
The UV absorbing materials, released from Yamahai-moto yeast during the citrate buffer incubation, were more than twice those from Sokujo-moto yeast.
The phosphorus content of Yamahai-moto yeast was lower than that of Sokujo-moto yeast in the almost every fraction, especially in the lipid fraction.
It is very interesting that the rate of dead cells, detected by methylene blue staining technique, in the final stage of the moromi process was 35 to 55% in Bozu-moromi wich was frequently produced by employing Sokujo-moto mash as a starter, whereas the rate was below 5 % in Futa-moromi produced generally by employing Yamahai-moto mash.
It was assumed from the above results that one of the most important differences of Yamahai moto and Sokujo-moto yeasts may be related to their permeabilitic barrier.