Production of ethanol in plants and some microorganisms

• Anaerobic respiration leading to the production of ethanol occurs in organisms such as certain bacteria and fungi (e.g. yeast) as well as some cells of higher plants (e.g. root cells under waterlogged conditions).
• The pyruvate molecule formed at the end of glycolysis loses a molecule of carbon dioxide and accepts hydrogen from reduced NAD to produce ethanol.
• The summary equation for the production of ethanol in plants/other microorganisms is: pyruvate + reduced NAD -> ethanol + carbon dioxide + oxidised NAD.
• Anaerobic respiration in yeast is used in the brewing industry. Yeast is grown in anaerobic conditions in which it ferments natural carbohydrates in plant products, such as grapes (wine production) or barley seeds (beer production) into ethanol.