<Li> Any energy - releasing metabolic process that takes place only under anaerobic conditions (becoming more scientific). </Li> <Li> Any metabolic process that releases energy from a sugar or other organic molecule, does not require oxygen or an electron transport system, and uses an organic molecule as the final electron acceptor (most scientific). </Li> <P> Fermentation is a process which does not necessarily have to be carried out in an anaerobic environment . For example, even in the presence of abundant oxygen, yeast cells greatly prefer fermentation to aerobic respiration, as long as sugars are readily available for consumption (a phenomenon known as the Crabtree effect). The antibiotic activity of hops also inhibits aerobic metabolism in yeast . </P> <P> Fermentation reacts NADH with an endogenous, organic electron acceptor . Usually this is pyruvate formed from the sugar during the glycolysis step . During fermentation, pyruvate is metabolized to various compounds through several processes: </P>

What is the main function of the fermentation pathway