<P> Fermentation products contain chemical energy (they are not fully oxidized), but are considered waste products, since they cannot be metabolized further without the use of oxygen . </P> <P> The chemical equation below shows the alcoholic fermentation of glucose, whose chemical formula is C H O . The reaction is catalysed by the enzymes pyruvate decarboxylase and alcohol dehydrogenase. One glucose molecule is converted into two ethanol molecules and two carbon dioxide molecules: </P> <Dl> <Dd> <Dl> <Dd> C H O → 2 C H OH + 2 CO </Dd> </Dl> </Dd> </Dl> <Dd> <Dl> <Dd> C H O → 2 C H OH + 2 CO </Dd> </Dl> </Dd>

Where do the 2 types of fermentation take place