264 FAMILY OF SACCHAROMYCETACEAE 



ascs usually contain 4 elliptical ascospores (2-2.5 /x). The wall of the 

 asc is broken when the spores germinate. Ger- 

 mination is by ordinary budding. On potato at 

 25 C., punctiform spherical colonies are formed 

 having a grayish white color. These become con- 

 fl uen ^ m to large colonies with festooned edges. 

 White confluent colonies develop on carrot. The 

 yeast ferments glucose. 



D. Fourth Sub-Group 

 Fig. 121-H. Sac- 

 charvmyces Etiennei Yeasts fermenting dextrose, but having no action 



ron '' on saccharose, maltose or lactose. 



SACCHAROMYCES MALI DUCLAUXI. Kayser 



This species was found by Kayser 1 in a sample of cider. The 

 cells are large (6 to 12 /* long and 4 to 7 IJL wide) and form a light float- 

 ing growth. They are killed at 55 C. and are very sensitive to acids. 

 Ascospores are formed at the end of 30 hours at 15 C. This yeast 

 acts on neither saccharose nor maltose but ferments invert sugar im- 

 parting a " bouquet " to the solutions. 



SACCHAROMYCES UNISPORUS. Jorgensen 2 



This yeast was discovered by Holm. By its action on sugars, it 

 is related to Saccharomyces mali Duclauxi. The cells are small and 

 oval. In old cultures, one may see the shape of the cells of Pasto- 

 rianus. The spores appear at the end of 40 hours at 25 C. After 

 72 hours at 15 C. only a few ascs are visible. The ascospores are round 

 and refractive. This yeast does not form a scum but simply a ring 

 in old cultures. 



E. Fifth Sub-Group 



Yeasts which ferment lactose. 



SACCHAROMYCES FRAGILIS. Jorgensen 3 



This yeast was encountered in kefir, an alcoholic milk produced 

 by the fermentation of S. fragilis and many Torula and many bac- 

 teria among which is Bacillus caucasicus. Saccharomyces fragilis pos- 



1 Kayser, E. Etudes sur la fermentation du cidre. Ann. Past. Inst. 4, 1890. 



2 Jorgensen, A. Die Mikroorganismen der Garungsindustrie, Berlin, 5th edi- 

 tion, Paul Parey, 1909. 



* Jorgensen, A. See reference for S. unisporus. 



