LIFE CYCLES 



1-3 



Table 1-1 

 General Relationships of Three Genera 



charomyces by transverse fission (fig. 1-3). Schizosaccharomyce's 

 is a tropical yeast with optimum growth at 37^C.; Saccharomyces 

 has an optimum at 30°C. Native tropical beers are usually made 

 with Schizosaccharomyces and temperate zone beers are made with 

 Saccharomyces. Saccharomyces spores have a waxy cover and for 

 that reason are "acid fast." This means that when tiiey are stained 

 with a strong dye they retain the stain after the stained cells have 

 been washed with a dilute acid. Schizosaccharomyces spores are 

 starchy. They stain blue -black with iodine (Schizosaccharomyces 

 Frontispiece) and are not acid fast. They have no waxy coating and 

 they contain starch. This distinguishes them from the Saccharo- 

 myces which do not store starch. No Saccharomyces can utilize 

 dextrin but Schizosaccharomyces possesses the ability. This is im- 

 portant industrially for much of the carbohydrates in some mashes 

 are dextrins and therefore unavailable to the customary yeasts; a 

 yeast capable of utilizing dextrins might be very useful in making 

 alcohol. The Schizosaccharomyces are generally weak fermenters, 



