ZYGOSACCHAROMYCES SOYA 209 



crinkles like crepe paper, increasing its thickness, and its color changes 

 to yellowish brown. After three weeks the film gradually falls down 

 and deposits a great deal of sediment on the bottom, leaving a thin 

 film over the surface, and at last only a few parts of the yeast ring 

 remain along the wall. In wort culture at 23 C., after keeping the 

 culture for seven days film does not form, although gas bubbles as- 

 cend through the medium. After three months a well-defined yeast 

 ring and thin film become observable, but this film has never been 

 folded at all. This species reproduces and forms its particular film 

 even in " Koji "-extract or " Shoju " which contains 23% of NaCl. 



It is most noticeable that this species forms a grayish brown, folded 

 film on the surface of sterilized " Shoju " after a long time, while other 

 races which we isolated from " Shoju-Moromi " cease the reproduction 

 of their cells in the same medium. 



This species ferments dextrose, maltose, levulose, but does not 

 ferment saccharose, lactose, raffinose, a-methylglucoside, galactose. 



It rarely produces spores in a yeast ring of "Koji "-extract cul- 

 tures after three months. After Gorodkowa's method, sporulation 

 occurs often after 10 days at 28 C. Following the diluted " Shoju " 

 method which has been described in the preceding plate, a large num- 

 ber of sporulated cells occur in the yeast ring after 4-5 days. The 

 spore is transparent with a somewhat thick wall; it is round or oval 

 in shape, 2.5-6 fj, in size, and contains a few tiny grains. The proc- 

 esses of formation and germination of spores in this yeast and other 

 relations are similar to the preceding yeasts. This yeast seems to be 

 identical with Zygosaccharomyces japonicus, Saito. 



Mitsuda and Nishimura have found in the fermentation of Soya 

 an asporogenic yeast. Kita has recently described a yeast similar to 

 Zygosaccharomyces major (Takahashi and Yukawa) which differs in 

 that galactose is not fermented. 



ZYGOSACCHAROMYCES SOYA? (Saito) Guilliermond 



This yeast was found with the preceding yeasts by Saito 1 in the 

 products from the preparation of Soya sauce and designated as Sac- 

 char omyces Soya. It is made up of spherical or oval cells (4 to 8 ju, 

 average size) with relatively resistant walls and homogeneous con- 

 tents with large vacuoles. (Fig. 86.) No ascospores are produced on 

 plaster blocks, or in yeast water to which dextrose has been added 

 or pure agar; abundant sporulation is observed, however, in the rings 

 formed on a decoction of Koji. The ascs are usually made up of two 



1 Saito, K. Mikrobiol. Studien uber die Soya-Bereitung. Cent. Bakt. 17, 

 1906. 



