Alcoholic fermentation – The anaerobic metabolic process by which sugars such as glucose, fructose, and sucrose, are converted into cellular energy and thereby producing ethanol, and carbon dioxide as metabolic waste products. Lactic acid fermentation – An anaerobic metabolic process by which sugars such as glucose, fructose, and sucrose, are converted into cellular energy and the metabolic waste product lactic acid. Chemosynthesis – The biological conversion of one or more carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e.g. hydrogen gas, hydrogen sulfide) or methane as a source of energy, rather than sunlight, as in photosynthesis.