therefore a type of disproportionation, and does not involve an overall change in oxidation state of the substrate. Most of the fermentative substrates are organic molecules. However, a rare type of fermentation may also involve the disproportionation of inorganic sulfur compounds in certain sulfate-reducing bacteria. See also Comproportionation Dismutase Oxidoreductase Fermentation (biochemistry) Citric acid cycle References Chemical reactions Chemical processes Organic reactions Biochemistry