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Nitrification. Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil. The process of complete nitrification may occur through separate organisms [1] or entirely within one organism, as in comammox bacteria.
Dissimilatory nitrate reduction to ammonium (DNRA), also known as nitrate/nitrite ammonification, is the result of anaerobic respiration by chemoorganoheterotrophic microbes using nitrate (NO 3−) as an electron acceptor for respiration. [1][2] In anaerobic conditions microbes which undertake DNRA oxidise organic matter and use nitrate (rather ...
Ammonification or Mineralization is performed by bacteria to convert organic nitrogen to ammonia. Nitrification can then occur to convert the ammonium to nitrite and nitrate. [44] Nitrate can be returned to the euphotic zone by vertical mixing and upwelling where it can be taken up by phytoplankton to continue the cycle. N
[12] [13] Complete nitrification, the conversion of ammonia to nitrate in a single step known as comammox, has an energy yield (∆G°′) of −349 kJ mol −1 NH 3, while the energy yields for the ammonia-oxidation and nitrite-oxidation steps of the observed two-step reaction are −275 kJ mol −1 NH 3, and −74 kJ mol −1 NO 2 − ...
Anammox, an abbreviation for "anaerobic ammonium oxidation", is a globally important microbial process of the nitrogen cycle [ 1 ] that takes place in many natural environments. The bacteria mediating this process were identified in 1999, and were a great surprise for the scientific community. [ 2 ] In the anammox reaction, nitrite and ammonium ...
Morphology and characteristics. Nitrobacter are gram-negative bacteria and are either rod-shaped, pear-shaped or pleomorphic. [1][2] They are typically 0.5–0.9 μm in width and 1.0–2.0 μm in length and have an intra-cytomembrane polar cap. [5][2] Due to the presence of cytochromes c, they are often yellow in cell suspensions. [5]
Figure 1: The nitrogen cycle in a soil-plant system. One potential pathway: N is fixed by microbes into organic compounds, which are mineralized (i.e. ammonification) and then oxidized to inorganic forms (i.e. nitrification) that are assimilated by plants (NO 3 −).
Simultaneous nitrification–denitrification (SNdN) is a wastewater treatment process. Microbial simultaneous nitrification - denitrification is the conversion of the ammonium ion to nitrogen gas in a single bioreactor. The process is dependent on floc characteristics, reaction kinetics, mass loading of readily biodegradable chemical oxygen ...