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Fermentation
It is a form of anaerobic respiration occurring in certain
microorganism. ATP (carrier of chemical energy) is generated in which
organic compounds act as both donors and acceptors of electrons.
In alcohol fermentation, pyruvate, the end product of glycolysis, is
converted to ethanol and carbon dioxide by eg. yeast
Pyruvate + NADH ¢ç (pyruvate
decarboxylase) ethanol + NAD+
Pyruvic acid
¯
Ethanol
In lactic acid fermentation, which occurs in many microorganisms
(when sugar is in short supply) by Lactobacillus acidophilus, in animal
cells the end product is lactic acid.
Micoorganisms display a range of fermentations, producing not only
ethanol or lactic acid but also other products, such as propionoic and
butyric acids, acetate, and methane.
pyruvate + NADH + H+ ¢ç (lactate
dehydrogenase) lactate + NAD+
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Pyruvic acid
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Lactic
acid
Ethanol
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