Yeast is a typical heterotrophic and facultative anaerobic microorganism, which can survive in aerobic and anaerobic environments. Yeast's demand for oxygen is variable. In the case of oxygen, it decomposes sugar into carbon dioxide and water, and yeast grows faster. In the absence of oxygen, yeast breaks down sugar into alcohol and carbon dioxide.

Physiological characteristics:

Yeast is a single-celled microorganism. It belongs to fungi of higher microorganisms. There are nuclei, cell membranes, cell walls, mitochondria, the same enzymes and metabolic pathways. Yeast is harmless and easy to grow. It exists in air, soil, water and animals. You can survive with or without oxygen.

Yeast is a facultative anaerobic organism, and no obligate anaerobic yeast has been found. In the absence of oxygen, fermentation yeast obtains energy by converting sugar into carbon dioxide and ethanol (commonly known as alcohol)

The genetic material composition of yeast: nuclear DNA, mitochondrial DNA and special plasmid DNA.