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July 30, 2026Short & citedBlog
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Field Notes • Biology

Yeast

Yeast is a group of unicellular fungi, with about 1,500 recognized species.

Updated July 30, 20261 min readCited sources

Yeast is a group of unicellular fungi, with about 1,500 recognized species. They are found worldwide and are important in food production, biotechnology, and some diseases.

What it is

Yeasts are single-celled fungi (eukaryotic microorganisms). Most belong to the phylum Ascomycota, with a smaller number in Basidiomycota. They reproduce mainly by budding, though some use fission.

Why it matters

Yeasts are essential in baking, brewing, and winemaking, especially Saccharomyces cerevisiae. They are also major model organisms in genetics and cell biology. Some yeasts cause infections in humans and animals, including Candida albicans.

Key details

Yeasts are widespread in nature—on plant surfaces, in soil, and in sugary habitats like fruits and flower nectar. They act as decomposers and nutrient recyclers. About 1,500 species are recognized.

In short

  • Yeasts are single-celled fungi.
  • Most are in Ascomycota.
  • Used in bread, beer, and wine.
  • Some species cause disease.
Canadian angle

Yeast is relevant to Canadian readers through baking, brewing, winemaking, food science, and microbiology research, all of which are active sectors in Canada.

Quick questions

What is yeast?
Yeast is a group of single-celled fungi that reproduce mainly by budding or fission.
What is Saccharomyces cerevisiae?
Saccharomyces cerevisiae is the best-known yeast species and is widely used in baking, brewing, and scientific research.
Can yeast cause disease?
Yes. Some yeast species are human or animal pathogens, including Candida albicans and certain related fungi.

Sources

  1. Britannicahttps://www.britannica.com/science/yeast-fungus
    Supports: Yeast as unicellular fungi; approximate species count; major phyla; ecological distribution; uses; pathogenic species.
  2. The Canadian Encyclopediahttps://thecanadianencyclopedia.ca/en/article/yeast
    Supports: Yeast as unicellular fungi; classification; budding and fission; Canadian-reader context.
  3. Saccharomyces Genome Databasehttps://wiki.yeastgenome.org/index.php/What_are_yeast%3F
    Supports: Yeast as single-celled fungi; phylum-level diversity; eukaryotic nature.
  4. Wikipediahttps://en.wikipedia.org/wiki/Yeast
    Supports: General overview of yeast diversity and reproduction; used cautiously alongside authoritative sources.
  5. Britannicahttps://www.britannica.com/science/Saccharomyces-cerevisiae
    Supports: Saccharomyces cerevisiae as baker's/brewer's yeast and its uses in food production and research.