Saccharomyces

Saccharomyces is considered a yeast, although this term is historical and ill-defined. Saccharomyces is a genus of fungus including many species. The distinct species of Saccharomyces are revised frequently as more research is done. All species are unicellular and capable of fermentation. Saccharomyces cerevisiae is the most well known species of yeast. It is used in the fermentation of beer, wine, and sake, and as a leavening agent in bread. It is commonly referred to as "ale yeast", "wine yeast", or "bread yeast". S. pastorianus, known as lager yeast, is a hybrid closely related to S. cerevisiae but is not a true species. S. cerevisiae is commonly studied as a model organism and was the first eukaryote to have its genome entirely sequenced.

See Lactobacillus, Pediococcus, Brettanomyces, Saccharomyces, and Mixed Cultures charts for other commercially available cultures.

Species

Saccharomyces cerevisiae is the type species of the genus Saccharomyces, although Saccharomyces paradoxus, S. cerevisiae's closest relative, is likely older and more globally ubiquitous than S. cerevisiae.

Species	Ecology	Notes
S. cerevisiae	Domestic: Beer, Wine, Bread. Wild: Fruit, Oak Trees.	Example
S. paradoxus	Oak trees	Example
S. eubayanus	Patagonia	Probable parent of lager yeast
S. mikatae	Decayed leaves in Japan	Example
S. kudriavzevii	Decayed leaves in Japan	Example
S. bayanus*	Wine	Possible hybrid of S. eubayanus and S. cerevisiae. Possible parent of S. pastorianus.
S. florentinus	Drosophila and sulphurized grape must	Example
Example	Example	Example

Many previously recognized species of Saccharomyces have been consolidated or reassigned to another genus, commonly Zygosaccharomyces.