ZYGOSACCHAROMYCES MAJOR 215 



ZYGOSACCHAROMYCES MAJOR. Takahashi and M. Yukawa l 



This yeast was isolated from samples taken at different stages 

 during the ripening of " Shoju." 



In "Koji "-extract or wort culture after 4 days at 20 C., the cells 

 are mainly spherical (3.7-7.5 /z), sometimes oval, their contents are 

 homogeneous, and sometimes exhibit vacuoles. The glycogen reac- 

 tion is evident in every cell. Cells in yeast ring of " Koji "-extract 

 culture after 20 days at 20 C. are so irregular that a cell may be as 

 small as 2.5 microns and as large as 10 microns. The occurrence of 

 these cells seems to be somewhat prolonged in wort or " Koji " 

 extract containing a quantity of salt. Old culture in the same 

 media after 2-6 months at room temperature exhibits not only the 

 cells which are similar to Will's film cells of the first generation, and 

 permanent cells, but also very highly elongated, mycelial ones. 



In " Koji "-extract or wort gelatine plate after 7 days at room 

 temperature this species forms grayish white, round, bright, waxy 

 colonies. On " Koji "-extract-agar plate after 30 days at 27 C. it 

 grows with somewhat brownish, waxy, dull lustered, elevated cover- 

 ing. Margin shows somewhat paralleled streamy canals. On glu- 

 cose-sake-agar after 10 days at 25 C. it forms a grayish white, waxy 

 covering with slightly elevated sides. The central part is somewhat 

 concaved and the marginal part dull toothed. On " Koji "-extract 

 gelatin stab after 30 days at 15 C. it forms waxy, feeble lustered, 

 brownish, elevated isles at the mouth of the stab canal, and rosary- 

 like colonies with gas bubbles along the canal. This species grows 

 in many fluid media, and according to the appearance of its fermenta- 

 tion it belongs to the so-called bottom yeasts. In " Koji "-extract 

 culture at 25 C. a yeast ring appears first after 3 days, but it does 

 not form any complete ring even after 6 months, -while the sedimental 

 yeast crop becomes somewhat plentiful after 3 weeks. Its develop- 

 ment in wort or hopped wort seems to be inferior to that in "Koji " 

 extract. Its resisting power against NaCl is so striking that it can 

 grow tolerably in " Koji " extract or wort containing 20% NaCl. 



According to Lindner's method this species ferments dextrose, 

 levulose, mannose, saccharose, maltose, but does not ferment galac- 

 tose, lactose, rafnnose, a-methyl-glucoside. 



This species is one of easily sporulable kind among all the Zygo- 

 saccharomyces isolated from " Shoju-Moromi." This yeast does not 

 form spores on gypsum-block at all. Sporulated cells occur very 

 rarely in yeast ring developed in " Koji "-extract culture after 3 to 6 



1 Takahashi, and Yukawa, M. Original communications, Eighth Internatl. 

 Congress of Applied Chemistry, V. XIV, 1912, p. 162. 



