Yeast

Yeasts are single-celled fungi, belonging mainly to the Ascomycetes, that serve as nutrient recyclers in nature, but are also important in industry, biotechnology, and as the agents of disease in humans. The term yeast is generically used in reference to many species of single-celled, budding fungi, including Saccharomyces—used in baking and brewing—and Candida—an infectious yeast common in people with compromised immune systems, such as AIDS victims.