WANI Dictionary

Fermentation

Fermentation was originally described by Louis Pasteur as “life without air,” but later usage has adopted more precise biochemical definitions. In biology, fermentation is generally defined as a catabolic process in which organic compounds serve as both electron donors and electron acceptors, with some definitions also permitting inorganic acceptors such as protons when they are generated metabolically. In industrial and biotechnological contexts, the term is sometimes applied more broadly to large‑scale biological production processes.

Definitions in the literature

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• Some living systems use an organic molecule (commonly pyruvate) as a final electron acceptor through a process called fermentation. Fermentation does not involve an electron transport system and does not directly produce any additional ATP beyond that produced during glycolysis by substrate-level phosphorylation [1].
• The simple definition (catabolism with organic compounds as electron donors and acceptors) works well in many cases (Fig. 1A). It correctly includes lactate and ethanol fermentation (Fig. 1A), the types of fermentation that appear most often in textbooks. It also correctly excludes nitrate respiration, sulfur respiration, homoacetogenesis, and methanogenesis [2].