Jäst kan arbeta i en miljö utan syre, men deras ämnesomsättning och produkter kommer att vara annorlunda .
Yeast is a facultative anaerobe, which means that they can survive in both aerobic and anaerobic environments. In an aerobic environment, yeast undergoes aerobic respiration, completely oxidizing and decomposing organic matter (such as glucose) through a series of complex biochemical reactions, producing a large amount of energy, while generating carbon dioxide and water. Denna aerob andningsmetod kan ge tillräcklig energi för tillväxt och reproduktion av jäst, vilket gör att den kan växa och dela snabbt .
However, in an anaerobic environment, yeast will undergo anaerobic respiration, also known as fermentation. At this time, organic matter (such as glucose) is incompletely decomposed, producing alcohol and carbon dioxide, while releasing less energy. This fermentation is widely used in processes such as winemaking and winemaking. For example, when making bread, the yeast in the dough will undergo aerobic respiration when exposed to oxygen in the air, rapidly reproduce, and produce a large amount of carbon dioxide, causing the dough to expand and ferment. When making wine, the sealed fermentation tank creates an anaerobic environment for the yeast, and the yeast converts glucose into alcohol and carbon dioxide through fermentation, thereby producerar alkoholhaltiga produkter .
Although yeast can survive and ferment in an anaerobic environment, long-term exposure to an anaerobic environment may limit its growth and metabolism. In addition, different types of yeast may have different requirements and tolerance for oxygen. Therefore, in practical applications, it is necessary to select appropriate fermentation conditions based on the type of yeast and the desired product.