In alcohol fermentation, when a glucose molecule is oxidized, ethanol (ethyl alcohol) and carbon dioxide are byproducts. The organic molecule that is responsible for renewing the NAD+ supply in this type of fermentation is the pyruvate from glycolysis. Each pyruvate releases a carbon dioxide molecule, turning into acetaldehyde. The acetaldehyde is then reduced by the NADH produced from glycolysis, forming the alcohol waste product, ethanol, and forming NAD+, thereby replenishing its supply for glycolysis to continue producing ATP.