Fermentation is

Explanation

In fermentation, the incomplete oxidation of glucose is achieved under anaerobic conditions by set of reactions where pyruvic acid is converted to `CO_(2)` & Ethanol. The ezymes, pyruvic acid decarboxylase and alcohol dehydrogenase catalyse these reactions. Two types of fermetations are :
1) Alcoholic fermentation
2) Lactic acid fermentation
1) Alcoholic fermentation : This -is most common type of fermentation process. In alcoholic fermentation, pyruvic acid is broken to ethyl alcohol & `CO_(2)` in two steps.
i)- The pyruvic acid is decarboxylated to acetaldehyde in the presence of enzyme pyruvic decarboxylase.
`CH_(3).CO.COOH overset("Pyruvic decarboxylase")to CH_(3).CHO + CO_(2)`
ii) Acetaldehyde is then reduced to ethyl alcohol by- `NADH^(+) + H^(+)` produced in glycolysis acetaldehyde is final hydrogen acceptor. The reaction is catalysed by alcohol dehydrogenase.
`underset("acetaldehyde")(CH_(3).CHO + NaDH) + H^(+) overset("alcoholic")underset("dehydrogense")to underset("ethylalcohol")(C_(2)H_(5)OH + NaD^(+))`
2) Lactic acid fermentation: Pyruvic acid formed at the end of glycolysis is converted to lactic acid by lactobacillus lactibacteria.
`underset(" Pyruvicacid ")(CH_(3).COCOOH + NADH + H^(+)) overset("Lactic acid dehydrogenase")underset(FMN, Zn^(+2)) to underset("lactic acid")(C_(3)H_(6)O_(3))`