General Information: Ammonia-oxidizing bacterium. This organism is an obligate chemo-lithoautotroph as it only uses ammonia and carbon dioxide and mineral salts for growth, and is an important part of the global biogeochemical nitrogen cycle. It can derive all energy requirements from the oxidation of ammonia to nitrate, driving global nitrogen from the reduced insoluble form to the oxidized and potentially gaseous form (including NO and NO2 which are greenhouse gases). The energy derived from ammonia oxidation is in turn used to drive carbon fixation. This bacterium also provides plants with a readily available form of nitrogen, is important in wastewater treatment, and may be involved in bioremediation of sites contaminated with toxic compounds.