Saccharomyces pastorianus

Saccharomyces pastorianus
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Saccharomycetes
Order:	Saccharomycetales
Family:	Saccharomycetaceae
Genus:	Saccharomyces
Species:	S. pastorianus
Binomial name
Saccharomyces pastorianus Nguyen & Gaillardin ex. Beijerinck
Synonyms
Saccharomyces carlsbergensis

Saccharomyces pastorianus is a yeast used industrially for the production of lager beer, and was named in honour of Louis Pasteur by the German Max Reess in 1870.^[1] This yeast's complicated genome appears to be the result of hybridisation between two pure species in the Saccharomyces species complex, a factor that led to difficulty in establishing a proper taxonomy of the species.

The now-defunct synonym Saccharomyces carlsbergensis was and continues to be used in scientific literature, but is invalid, as the name Saccharomyces pastorianus (Reess 1870) has taxonomic precedence. The name S. carlsbergensis is typically attributed to Emil Christian Hansen from the era when he worked for the Danish brewery Carlsberg in 1883,^[2] but in actuality it was not officially described by Hansen as a distinct species^[3] until 1908, along with another synonym, Saccharomyces monacensis.^[4] The type strains of both synonyms are currently stored in yeast banks under the taxonomic name S. pastorianus.^[5]