Fermentation

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Fermentation
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Sucrose is a simple dimer of glucose and
fructose, both of which can be used as
substrates for fermentation to produce ethanol.
The yeast itself produces the enzyme invertase,
which splits the sugar in half.
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zymaseC6H12O6 2 C2H5OH 2
CO2
The basic fermentation reaction
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• The sugar present in the grape juice as glucose,
  C6H12O6, is converted to pyruvate during a long
  and complicated biochemical pathway called
  glycolysis. 
• Under the anaerobic conditions found in the wine
  bottle, the pyruvate is eventually converted by
  the yeast to carbon dioxide and ethanol.

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The final steps of the reaction

• (1)  The pyruvate decarboxylated to acataldahyde,
  releasing CO2 gas.                         

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• (2)  The acetaldehyde is now reduced to produce
  ethanol.

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Enzymes

• Catalysts speed up reactions by lowering
  activation energy and providing an alternate
  reaction pathway.
• Each enzyme is very specific.