One example is Saccharomyces cerevisiae, which is used in making bread, wine, and beer, and for human and animal health.

The inability to use nitrate and ability to ferment various carbohydrates are typical characteristics of Saccharomyces.

It was not until 1876 that Louis Pasteur demonstrated the involvement of living organisms in fermentation and in 1883, Emil C. Hansen isolated brewing yeast and propagated the culture, leading to the discovery of the importance of yeast in brewing.

[1] The use of microscopes for the study of yeast morphology and purity was crucial to understanding their functionality.

Saccharomyces yeasts can form symbiotic matrices with bacteria, and are used to produce kombucha, kefir and ginger beer.

Saccharomyces fragilis, for example, is part of kefir cultures[2] and is being grown on the lactose contained in whey (as a byproduct in cheesemaking) to be used as animal fodder itself.

[5] Case report suggest extended exposure to S. cerevisiae can cause hypersensitivity in humans.