What is yeast protein?

Dietary protein derived from cultivated yeast cells—neither animal nor plant, but microbial protein.

Scientifically reviewed: September 25, 2026

Yeast is neither plant nor animal

Yeast belongs to the kingdom Fungi. Humans have used species including Saccharomyces cerevisiae in bread, beer and wine for centuries. Modern food technology can cultivate yeast for a different purpose: concentrated dietary protein.

What does microbial protein mean?

Microbial protein—sometimes discussed under the broader term single-cell protein—is obtained from microorganisms such as yeast, fungi, algae or bacteria. The cells contain protein alongside carbohydrates, lipids, minerals and other components; processing can concentrate selected fractions.

Nutritional yeast

Whole or minimally processed inactive yeast, mainly used for flavor and nutrition.

Yeast extract

A soluble fraction commonly used for savory or umami flavor.

Baker’s yeast

Living yeast used to ferment dough. It is not protein powder.

Mycoprotein

Protein-rich biomass from filamentous fungi rather than conventional yeast cells.