Use
Yeasts are single-celled microscopic plants classified as
one of the forms of fungi, Some yeasts cause diseases of
skin and mucous membranes, whereas some others
(notably the strains of Saccharomyces cerevisiae, baker's
yeast) are used in baking and brewing.
Yeasts employ one or both of the metabolic processes
of fermentation and respiration, fermentation involving
anaerobic decomposition of hexose sugars into alcohol
and carbon dioxide, and respiration involving exothermic
decomposition of various sugars, in the presence of
oxygen, to give carbon dioxide and water.
Yeasts are grown also for use as a source of food rich
in β-complex vitamins.