yeast

any of a group of fungi in which the body (mycelium) consists of individual cells, which may occur singly, in groups of two or three, or in chains. Yeasts reproduce by budding and by the formation of sexual spores (in the case of the perfect yeasts) or asexual spores (in the case of the imperfect yeasts). Baker's yeast (Saccharomyces) ferments carbohydrates to produce alcohol and carbon dioxide and is important in brewing and breadmaking. Some yeasts are a commercial source of proteins and of vitamins of the B complex. Yeasts that cause disease in humans include CANDIDA , CRYPTOCOCCUS , and PITYROSPORUM .