Fermentation is anaerobic.
Fermentation is a metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation. Importantly, fermentation does not require oxygen. It's an alternative pathway to cellular respiration when oxygen is limited or unavailable. In contrast, aerobic respiration, which also breaks down glucose, does require oxygen to produce energy (ATP).
In summary, fermentation represents an anaerobic route for generating energy from glucose.
