anaerobic respiration energy derivation by oxidation of reduced inorganic compounds ammonia oxidation anaerobic respiration, using ammonium as electron donor The oxidation of ammonium (NH4) to nitrogen (N2) in the absence of oxygen, using nitrite (NO2) as the electron acceptor. It is suggested that hydroxylamine and ammonium are combined to yield hydrazine, which is subsequently oxidized to N2. Wikipedia:Anammox GO:0019331 anaerobic ammonium oxidation anammox biological_process MetaCyc:P303-PWY cellular nitrogen compound metabolic process