Anaerobic oxidation of ammonium is a biologically mediated process

作者：Astrid A. van de Graaf, A. Mulder, Peter de Bruijn, Mike S. M. Jetten, Lesley Anne Robertson, Johannes Gijs Kuenen · 发表于：Applied and Environmental Microbiology · 年份：1995 · DOI：10.1128/aem.61.4.1246-1251.1995 · 被引用次数：854 · 研究领域：Wastewater Treatment and Nitrogen Removal、Microbial metabolism and enzyme function、Water Treatment and Disinfection

A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in the ammonium and nitrate concentrations were observed. Chemical reactions could therefore not be responsible for the ammonium conversion. The addition of chloramphenicol, ampicillin, 2,4-dinitrophenol, carbonyl cyanide m-chlorophenyl-hydrazone (CCCP), and mercuric chloride (HgIICl2) completely inhibited the activity of the ammonium-oxidizing sludge. Furthermore, the rate of ammonium oxidation was proportional to the initial amount of sludge used. It was therefore concluded that anaerobic ammonium oxidation was a microbiological process. As the experiments were carried out in an oxygen-free atmosphere, the conversion of ammonium to dinitrogen gas did not even require a trace of O2. That the end product of the reaction was nitrogen gas has been confirmed by using 15NH4+ and 14NO3-. The dominant product was 14-15N2. Only 1.7% of the total labelled nitrogen gas produced was 15-15N2. It is therefore proposed that the N2 produced by the Anammox process is formed from equimolar amounts of NH...