Yeast

Article By:

Fell, Jack W. Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Key Biscayne, Florida.

Phaff, Herman J. Department of Food Science and Technology, College of Agricultural and Environmental Sciences, University of California, Davis, California.

Walker, Graeme M. School of Molecular and Life Sciences, University of Abertay Dundee, Dundee, United Kingdom.

Last reviewed:March 2021

DOI:https://doi.org/10.1036/1097-8542.753100

Show previous versions

• Yeast, published June 2014:Download PDF Get Adobe Acrobat Reader

A collective name for those fungi that possess, under normal growth conditions, a vegetative body (thallus) consisting, at least in part, of simple, single cells. Yeasts are a phylogenetically diverse group of organisms that occur in two divisions or phyla of fungi, namely, Ascomycota and Basidiomycota. More than 1500 species have been described, but these possibly represent only 1% of the total number of species in nature; thus, the majority of yeasts have yet to be discovered. Yeasts play a large part in industrial fermentation processes, including the production of industrial enzymes and chemicals, food products, industrial ethanol, and malt beverages and wine; in diseases of humans, animals, and plants; in food spoilage; and as a model of molecular genetics (for example, Schizosaccharomyces pombe is a notable model organism; Fig. 1). In yeast, the cells making up the thallus occur in pairs, in groups of three, or in straight or branched chains consisting of as many as 12 or more cells. Vegetative reproduction is characterized by budding or fission. Sexual reproduction also occurs in yeast, and it is differentiated from that of other fungi by sexual states that are not enclosed in a fruiting body. See also: Beer; Distilled spirits; Fermentation; Food fermentation; Fungi; Mycology; Wine; Yeast systematics

The content above is only an excerpt.