288 FAMILY OF SACCHAROMYCETACEAE 



but in scums on beer wort they appear very rarely. The temperature 

 limits for sporulation are 2-3 C. and 30 C. This yeast ferments 

 dextrose, levulose, saccharose, mannose and raffinose. 



WILLIA SATURNUS. Klocker 

 Syn.: SACCHAROMYCES SATURNUS. Klocker 



This yeast was found by Klocker l in a sample of earth from 



Himalaya. It has since been found in Italy and Denmark. It de- 



^ velops on must with a white wrinkled growth and a 



Q,Hu - sediment. In a young scum, the cells are globular 



"$'Q? or oval in shape (4 to 6/x) (Fig. 135). Later they 



enlarge, become spherical and filled with globules of 

 fat. At the same time the scum increases, great 

 & bubbles of carbon dioxide are formed and the color 



Fig. 135. Willia becomes yellow. If the culture is shaken the scum 



Satwmua. Cells of will fall to the bottom of the culture flask and a ring 



Scum on Beer . 



Wort after 24 is formed around the culture flask. 



Hours at 25 C. ^he temperature limits for budding on beer wort 



are 2 to 4 C. and 35 to 37 C. The optimum is 



situated between 28 and 30 C. The scum forms easily on yeast 



water to which pure saccharose is added. Maltose, dextrose or 



levulose also serve well. 



Sporulation is rapidly accomplished on plaster blocks. The tem- 

 perature limits are 4 to 7 C. and 28 to 31.5 C. The optimum is near 

 25 C. At this last temperature, the ascospores appear at the end of 

 43 hours. They also develop abundantly in the scum 

 on yeast water and rice. They appear both in the ^y 



ring in the side of the culture tube and in the scums *-* ^ 



of cultures on must and also in old cultures on gelatin. " *3r 

 The shape of the ascospore is that of a lemon but Fig. 136. Ascs 

 sometimes the points are less evident and indistinct. ?aftp P VifiS!r^ 



\dtL Lt?i xYlUClvtM^ * 



The ascospore is always girdled with a projecting ring, 

 which reminds one of the planet Saturn, indicating the origin of the 

 name of this yeast. In the interior of the cells, there is a globule 

 probably of fat. The length of the ascospore is about 3/i and the 

 width 2//. The ascs include generally two ascospores, sometimes three, 

 rarely one, and exceptionally four. The germination of the ascospores 

 operates by budding. Often it is preceded by a fusion of ascospores 

 two by two which is accompanied by a nuclear fusion constituting a 

 true copulation (parthenogamy) (Fig. 39). 



1 Klocker, A. Une espece nouvelle de la famille Sacchar. (S. saturnus). 

 Comp. Rend, des trav. lab. de Carlsberg, 6, 1903. 



