Lactic aci fermentation is a biological process by which sugars such as glucose, fructose, and sucrose, are converted into cellular energy and the metabolic waste product lactic acid. It is a form of fermentation that occurs in some bacteria and animal cells in the absence of oxygen. During homolactic acid fermentation, one molecule of glucose is ultimately converted to two molecules of lactic acid. In heterolactic acid fermentation, sometimes referred to as the phosphoketolase pathway, the products of fermentation are one molecule of carbon dioxide, one molecule of ethanol, and one molecule of lactic acid