JOURNAL OF THE SOCIETY OF BREWING,JAPAN

(1) We asceatained the existence of glycine, alanine, valine, leucine (or isoleucine), arginine, histidine, lysine, phenylalanine, tyrosine, cystine, methionine, glutamic acid, aspartic acid, and proline in the free state.
(2) And we also recognized that the R_F-values of amino-acids were influenced by NaCl in Shoyu.

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We have tried to study possible variations of sake yeasts in the course of repeating the inoculation on five sorts of koji-extract media which. contained different amount of, sugar, acid (lactic acid) and alcohol. Now that inoculation attained to about 300th time after four years, their fermenting powers were determined.
As the amount of yeast to be added to the fermentable medium was not constant in former methods, we made the tests in two well-deffined manners: “one-fifteenth” and “fundamental” tests of fermenting powers. This report concerns the former tests. The numerical value of one-fifteenth is due to the ratio of “mother” to “main” mash in sake-brewing, which is 1: 15. Fermentation test each preculture was not brought back to that on a standard medium, but it was carried out on the same medium as used for acclimatization.
The results can be summarized as follows:
(1) Concerning the influence of the concentration of sugar in the preculture, it was found that the yeasts acclimatized for lower concentration had greater fermenting power than those acclimatized for higher concentration, except for the fermentation test in the medium containing both alcohol and lactic acid (No.5).
(2) Alcohol and acid (actic acid) have a very delicate relation with the multiplication and fermenting power of sake yeast.
(3) The yeasts acclimatized to lactic acid have generally greater fermenting power than the others.
(4) The five acclimatized yeasts of the yeast No.6 may have the possibility of presenting variations and mutations. This is especially noticeable in the yeasts acclimatized to alcohol (No.3 and No.5).
(5) It should be pointed out that there are sometimes found similar phenomena in the acclimatization of the yeast to those noted in the case of agricultural crops, where the rotation of crops is superior to the continuous cultivation of the same crop on the same land. This was supposed to be caused by a certain defect of the standard sterilized koji-extract as a nutrient medium of the yeast.

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