Nitrification - Fundamentals of the metabolism and problems at the use of ammonia oxidizers

From an ecological point of view, a great problem results from the release of increasing amounts of inorganic and organic nitrogen compounds. Apart fr om gaseous nitrogen compounds, such as the greenhouse gas N2O, soluble nitr ogen compounds such as ammonium cause difficulties. In recent years, great progress has been made regarding the reduction of the emission of sulfur an d phosphorus compounds. Since there are no effective strategies for the dec rease of nitrogen releases, the emission of such compounds has even been in creasing. Therefore, great efforts are being made to eliminate the soluble nitrogen compounds in particular, for example in wastewater treatment plant s. A decisive meaning befits the chemolithoautotrophic ammonia oxidizers. This review focuses on the ecological consequences of the release of ammoni a in particular, the metabolism of the ammonia oxidizing microorganisms und er consideration of the latest research results, and the problems that aris e in the context of using these bacteria for the removal of ammonia.