Fermentation

Fermentation is an incomplete oxidation of an organic substrate. During fermentations an electron donor becomes reduced and energy is trapped through substrate-level phosphorylation. Fermentation products include pyruvate if the glycolytic pathway is used or lactate formate, 2, 3-butanediol and ethanol from the butanediol pathway used by Klebsiella, Erwinia, Enterobacter, and Serratia spp.  Or succinate, ethanol, acetate and formate from a mixed acid fermentation found in Escherichia, Salmonella, and Shigella spp