Written and maintained by CASRAI Editorial Board
Last updated
Short answer
Saccharomyces cerevisiae is budding yeast, the single-celled fungus used for baking and brewing and the most intensively studied eukaryote in basic research. Its 16-chromosome genome was the first completely finished eukaryotic genome, and the reference strain S288C is a deliberately bred laboratory mosaic, not a wild isolate. This page is general scientific information, not medical advice.
Definition and scope: what is Saccharomyces cerevisiae?
S. cerevisiae (also written “what is S. cerevisiae” or “Saccharomyces cerevisiae yeast”) is a unicellular fungus that reproduces by budding. A 2020 review calls it “the best studied eukaryote and a valuable tool for most aspects of basic research on eukaryotic organisms”, because nearly all biological functions found in eukaryotes are present and well conserved in it, it is unicellular, and it is easy to manipulate genetically (Parapouli et al., AIMS Microbiology 2020). Cerevisiae is the species epithet, and the same organism is called baker’s yeast or brewer’s yeast depending on use. Where yeast sits among the other fungi is covered in what is mycology.
What is Saccharomyces cerevisiae used for in the production of food, drink and fuel?
The same review credits its fermentation capacity, which produces alcohol and CO2, together with resilience to adverse osmolarity and low pH, for its use in food, beverage (especially wine) and biofuel production. The review notes that some of these uses date back several thousands of years, which is unusual for a model organism.
How it is used in the lab: the first sequenced eukaryotic genome
Engel et al. (G3, 2014) state that “the 16 chromosomes of Saccharomyces cerevisiae comprise the first completely finished eukaryotic genome.” Sequencing was launched in 1989, the genome was released in 1996, and about 6,000 protein-coding genes were originally identified, many of unknown function. The Saccharomyces Genome Database (SGD) took over annotation and maintenance of the reference in the early-to-mid 2000s. The genome comprises 16 nuclear chromosomes plus a separate mitochondrial genome.
Laboratory strains: why S288C is a mosaic
The reference sequence is from strain S288C. Engel et al. describe it as “a contrived strain produced through numerous deliberate crosses” by the geneticists Lindegren and Mortimer, with almost 90% of its gene pool derived from EM93, an isolate from a fig in California in 1938. Two practical consequences follow for anyone writing a methods section: a laboratory strain is a bred background, so results are tied to the strain used, and the strain name belongs in the methods. The Parapouli review separately examines wild and environmental isolates as a reservoir of variation for industrial use.
Where researchers find yeast data and tools
SGD describes itself as providing “comprehensive integrated biological information for the budding yeast Saccharomyces cerevisiae“. Its home page lists the following resources.
| SGD resource | What the site lists it as |
|---|---|
| Strains | List of commonly used strains |
| Strain Variant Viewer, Align Strain Sequences | Strain-level sequence comparison tools |
| Design Primers, Restriction Site Mapper | Sequence analysis tools |
| AllianceMine | Data-mining tool |
| Nomenclature | Gene name registration |
| Submit Data, Community Forum, Colleague Information, Education, Meetings | Community and data-submission pages |
Yeast also turns up as a contaminant of other cultures; see cell culture contamination, aseptic technique and potato dextrose agar plates for fungal growth media.
Types or related concepts
- Laboratory strain versus wild or environmental isolate. The reference strain S288C is a bred mosaic (Engel et al. 2014), whereas the Parapouli review examines wild and environmental isolates as a reservoir of variation for industrial use. The two are not interchangeable backgrounds.
- Baker’s, brewer’s and wine yeast. These are use-based names for the same species, S. cerevisiae (Parapouli et al. 2020).
- S. boulardii. Named separately in the clinical literature on Saccharomyces fungemia (Vinayagamoorthy et al. 2023), where it appears as the probiotic used by most of the analysed cases. This page does not treat it further.
Where it matters for labs and clinics
Two points follow from the sources cited here. First, because S288C is a contrived strain and results are tied to the background used, the strain name belongs in a methods section, and the Strains list at SGD is one place to check commonly used names. Second, yeast is a recognised cause of fungal growth in other cultures, and clinical reports of Saccharomyces fungemia exist (Vinayagamoorthy et al. 2023). Contamination handling is covered in cell culture contamination and aseptic technique; clinical decisions are outside the scope of this page.
Common misunderstandings
- The reference strain is not a wild type. S288C is a bred mosaic (Engel et al. 2014).
- “Yeast” is not one species. This page concerns S. cerevisiae; the probiotic S. boulardii is named separately in the clinical literature cited below.
- Genome finished does not mean genes understood. Many of the roughly 6,000 genes originally had no known function.
Frequently asked questions
What is Saccharomyces cerevisiae?
Budding yeast: a single-celled fungus used in baking, brewing and as a eukaryotic model organism, with the first fully sequenced eukaryotic genome.
What is Saccharomyces cerevisiae used for in the production of?
Food, beverages (especially wine) and biofuels, per Parapouli et al. (2020), as well as basic research.
How is yeast made for bread?
Baking uses S. cerevisiae for its fermentation, which produces CO2 and alcohol. Commercial yeast manufacturing is not described in the sources cited here, so it is not covered.
What disease is caused by Saccharomyces cerevisiae?
Saccharomyces fungemia (bloodstream infection) is reported in the clinical literature. A 2023 systematic review in Medical Mycology (Vinayagamoorthy et al.) identified 117 cases across June 2005 to March 2022; 67.6% of the 108 analysed cases involved patients treated with S. boulardii probiotics and the all-cause mortality rate of the total cohort was 36.1%. This page gives general epidemiology only and no clinical guidance.
What does it mean if Saccharomyces cerevisiae IgA is high?
Interpreting an individual antibody result is a clinical question for the treating clinician and is outside the scope of this page.
Sources
- Engel SR et al. The reference genome sequence of Saccharomyces cerevisiae: then and now. G3 2014. PMC3962479 (checked 2026-11-07).
- Parapouli M et al. Saccharomyces cerevisiae and its industrial applications. AIMS Microbiology 2020;6(1):1-31. PMID 32226912 (checked 2026-11-07).
- Vinayagamoorthy K et al. Epidemiology of Saccharomyces fungemia: a systematic review. Med Mycol 2023. PMID 36806741 (checked 2026-11-07).
- Saccharomyces Genome Database. yeastgenome.org (checked 2026-11-07).
