Comammox

Comammox (COMplete AMMonia OXidation) is the name attributed to an organism that can convert ammonia into nitrite and then into nitrate through the process of nitrification.[1] Nitrification has traditionally been thought to be a two-step process, where ammonia-oxidizing bacteria and archaea oxidize ammonia to nitrite and then nitrite-oxidizing bacteria convert to nitrate.[2][3] Complete conversion of ammonia into nitrate by a single microorganism was first predicted in 2006.[1] In 2015 the presence of microorganisms that could carry out both conversion processes was discovered within the genus Nitrospira, and the nitrogen cycle was updated.[4][5] Within the genus Nitrospira, the major ecosystems comammox are primarily found in natural aquifers and engineered ecosystems.[6]

Complete nitrification step yield more energy (∆G°′ = −349 kJ mol−1 NH3) than either single oxidation alone (∆G°′ = −275 kJ mol−1 NH3 for ammonia oxidation to nitrite and ∆G°′ = −74 kJ mol−1 NO2− for nitrite oxidation to nitrate).[5]

  1. ^ a b Costa, E; Pérez, J; Kreft, JU (May 2006). "Why is metabolic labour divided in nitrification?". Trends in Microbiology. 14 (5): 213–9. doi:10.1016/j.tim.2006.03.006. PMID 16621570.
  2. ^ Winogradsky, Serge (1892). "Contributions a la morphologie des organismes de la nitrification". Arch. Sci. Biol. 1: 87–137.
  3. ^ Lawson, Christopher E; Lücker, Sebastian (2018-04-01). "Complete ammonia oxidation: an important control on nitrification in engineered ecosystems?". Current Opinion in Biotechnology. Energy biotechnology • Environmental biotechnology. 50: 158–165. doi:10.1016/j.copbio.2018.01.015. hdl:2066/195181. ISSN 0958-1669. PMID 29414055.
  4. ^ van Kessel, MA; Speth, DR; Albertsen, M; Nielsen, PH; Op den Camp, HJ; Kartal, B; Jetten, MS; Lücker, S (26 November 2015). "Complete nitrification by a single microorganism". Nature. 528 (7583): 555–9. Bibcode:2015Natur.528..555V. doi:10.1038/nature16459. PMC 4878690. PMID 26610025.
  5. ^ a b Daims, H; Lebedeva, EV; Pjevac, P; Han, P; Herbold, C; Albertsen, M; Jehmlich, N; Palatinszky, M; Vierheilig, J; Bulaev, A; Kirkegaard, RH; Bergen, MV; Rattei, T; Bendinger, B; Nielsen, PH; Wagner, M (26 November 2015). "Complete nitrification by Nitrospira bacteria". Nature. 528 (7583): 504–9. Bibcode:2015Natur.528..504D. doi:10.1038/nature16461. PMC 5152751. PMID 26610024.
  6. ^ Cite error: The named reference :4 was invoked but never defined (see the help page).