Saccharomyces pastorianus
（重定向自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. This yeast's complicated genome appears to be the result of hybridisation between two pure species in the Saccharomyces species complex, a factor that has that led to difficulty in establishing a proper taxonomy of the species.