NL·0206Herbarium of the Nature Library
- Name
- Saccharomyces cerevisiae
- Family
- Saccharomycetaceae
- Native to
- Wild ancestors in East Asia (oak bark and fruit); now cosmopolitan through domestication
- Habitat
- Fruit surfaces, Tree bark, Human fermentation
Baker's and brewer's yeast
Saccharomyces cerevisiae
Also calledKhamir (Hindi/Urdu) · Khamira (Arabic/Persian, 'leaven') · Jiaomu 酵母 (Chinese) · Hefe (German) · Levure (French)
A single-celled fungus behind bread, beer and wine for at least 5,000 years. It was the first eukaryote to have its genome fully sequenced (1996), and it is still one of biology's most important model organisms.
Saccharomyces cerevisiae, also called brewer's yeast or baker's yeast, is a species of yeast. The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes. It is one of the most intensively studied eukaryotic model organisms in molecular and cell biology, much like Escherichia coli as the model bacterium. It is the microorganism which causes many common types of fermentation. S. cerevisiae cells are round to ovoid, 5–10 μm in diameter. It reproduces by budding. Wikipedia
What it can do
- iFerments sugars to ethanol and carbon dioxide even when oxygen is present (the Crabtree effect)
- iiReproduces by budding, about every 90 minutes in rich medium
- iiiShares thousands of genes with humans; many human genes can replace their missing yeast counterparts
- ivUnder starvation, forms four hardy spores in an ascus (a tetrad)
At the table
Eatenwhole cells (in bread, beer; inactivated as nutritional yeast)
Safe and eaten worldwide. Live yeast can cause bloating. The probiotic variety S. cerevisiae var. boulardii has very rarely caused bloodstream infections in seriously ill patients with central lines.
In the medicine cabinet
| Tradition | Use |
|---|---|
| Modern medicine | S. cerevisiae var. boulardii (Saccharomyces boulardii) probiotic for antibiotic-associated and infectious diarrhoea |
| Biotechnology | Engineered strains produce insulin, hepatitis B vaccine antigen and artemisinic acid |
| Folk nutrition | Brewer's yeast taken as a B-vitamin and chromium supplement |
Weight of evidence
Moderate. Some clinical trials with promising but limited or mixed results.
Active compounds
B vitamins, β-glucans, glutathione
Fruiting body & spores
Spores
Ascospores, four per ascus (a tetrad), round, about 3–5 µm; cells ovoid, about 5–10 µm. No mushroom or spore print
- Dispersal
- Carried by insects (wasps and fruit flies) between fruits and trees, and by people through fermentation
How to cultivate it
Hardiness (USDA zones)
- Light
- Not needed
- Water
- Moist dough or liquid
- Soil
- Flour-and-water or sugary liquid (wort, must)
- Propagation
- A pinch of dried yeast or a portion of active starter
- To harvest
- Hours (bread rise) to weeks (beer, wine)
- Climates
- Any (indoors)
- 1Dissolve yeast in lukewarm water (about 30–35 °C; above about 50 °C kills it)
- 2Mix into flour or sugary liquid; for wild leaven, keep a flour-and-water starter and feed it daily
- 3Keep at about 24–30 °C for bread, or 15–22 °C for most ales and wines
- 4Bubbles and rising show active fermentation; bake, or bottle when fermentation ends
Where it lives
Recorded sightings
—
geo-referenced records in GBIF, from museums, herbaria and field observers.
Native range
Wild ancestors in East Asia (oak bark and fruit); now cosmopolitan through domestication
Drag the globe to turn it. Dots are where records exist, not a range map; darker means more records.
In the stacks
Searching the stacks…
Every page naming Saccharomyces cerevisiae in the Biodiversity Heritage Library →
Marginalia
Residue in pottery from Jiahu, China (about 7000 BCE) shows fermented rice-honey-fruit drinks. Ancient Egyptian bakers and brewers worked side by side. Louis Pasteur proved in 1857–60 that living yeast cells cause fermentation.
Curiosity
Leland Hartwell's 'cell division cycle' (cdc) mutants in this yeast helped win the 2001 Nobel Prize for discovering how cells control division, a mechanism shared with human cells.
Kinship
Photographs: iNaturalist contributors under the licences shown. Records: GBIF.org. Historical plates: Source Library (CC BY-SA 4.0; originals public domain). Summary text: Nature Library editors and Wikipedia (CC BY-SA). Medicinal and edibility notes are historical and educational, not advice. iNaturalist taxon 123330.