In its biochemical sense, fermentation is metabolism that obtains ATP from breakdown of organic substrates without a respiratory electron transport chain. The alcoholic route is one example; not every fermentation produces ethanol. See Clark, Douglas and Choi, Biology 2e, 7.5: fermentation versus anaerobic respiration.
A historical operational grouping of transformations producing gum-like material and sometimes mannitol, rather than one universal stoichiometric reaction.
The historical name for microbial oxidation of ethanol into acetic acid with oxygen. Its aerobic metabolism differs from the narrow biochemical definition of fermentation.
Microbial production of butyric acid or butyrate from suitable organic substrates, sometimes accompanied by carbon dioxide and hydrogen.
Microbial conversion of suitable substrates into lactate or lactic acid, with pathways and accompanying products depending on the organism.
Microbial digestion in enlarged caecal or colonic regions after the principal small-intestinal digestive region. Intake, particle sorting and retention affect its consequences for nutrition.
Reingestion of selected caecal material, allowing a later digestive passage to recover nutrients including microbial products. It is more specific than indiscriminate faeces consumption.
Microbial digestion in an enlarged compartment before the principal acid and enzymatic digestive regions. Independent specializations occur in ruminants, colobine monkeys and macropods.
Return of previously swallowed material to the mouth for further chewing, followed by reswallowing. It helps expose plant material to microbial attack.
Alcoholic fermentation produces ethanol and carbon dioxide from sugars through an enzyme-catalyzed pathway. See Saccharomyces cerevisiae for its ideal glucose balance and yeast for the distinction between living cells and active extracts.
