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Physiology and Distribution of Anaerobic Oxidation of Methane by Archaeal Methanotrophs
Published in Chiara Cassarini, Anaerobic Oxidation of Methane Coupled to the Reduction of Different Sulfur Compounds as Electron Acceptors in Bioreactors, 2019
AOM coupled to denitrification was first hypothesized to occur in a similar syntrophic manner as AOM coupled to SR (Raghoebarsing et al., 2006). However, Ettwig et al. (Ettwig et al., 2010) showed that CH4 oxidation coupled to nitrite reduction occurs in the absence of archaea. The bacterium “Candidatus Methylomirabilis oxyfera” couples AOM to denitrification, with nitrite being reduced to nitric oxide which is then converted to nitrogen (N2) and oxygen (O2). The thus generated intracellular byproduct oxygen is subsequently used to oxidize CH4 to CO2 (Ettwig et al., 2010). Moreover, recent studies reveal that a distinct ANME, affiliated to the ANME-2d subgroup and named “Candidatus Methanoperedens nitroreducens” (Figures 2.2C and 2.3), can carry out AOM using nitrate as the terminal electron acceptor through reversed methanogenesis (Haroon et al., 2013). In the presence of ammonium, the nitrite released by this ANME-2d is then reduced to N2 by the anaerobic ammonium-oxidizing bacterium (anammox) “Candidatus Kuenenia spp.”; while in the absence of ammonium, nitrate is reduced to N2 by “Candidatus Methylomirabilis oxyfera”. Therefore, different co-cultures are dominated in a biological system depending on the availability of the nitrogen species (nitrate, nitrite or ammonium) (Haroon et al., 2013).
Physiology and Distribution of Anaerobic Oxidation of Methane by Archaeal Methanotrophs
Published in Susma Bhattarai Gautam, Performance Assessment and Enrichment of Anaerobic Methane Oxidising Microbial Communities from Marine Sediments in Bioreactors, 2018
AOM coupled to denitrification was first hypothesized to occur in a similar syntrophic manner as AOM-SR (Raghoebarsing et al., 2006). However, Ettwig et al. (2010) showed that CH4 oxidation coupled to nitrite reduction occurs in the absence of archaea. The bacterium "Candidatus Methylomirabilis oxyfera" couples AOM to denitrification, with nitrite being reduced to nitric oxide which is then converted to nitrogen and oxygen. Thus generated intracellular byproduct oxygen is subsequently used to oxidize CH4 to CO2 (Ettwig et al., 2010). Moreover, recent studies reveal that a distinct ANME, affiliated to the ANME-2d subgroup and named "Candidatus Methanoperedens nitroreducens" (Figure 2.2C and 2.3), can carry out AOM using nitrate as the terminal electron acceptor through reversed methanogenesis (Haroon et al., 2013). In the presence of ammonium, the nitrite released by this ANME-2d is then reduced to nitrogen by the anaerobic ammonium-oxidizing bacterium (anammox) "Candidatus Kuenenia spp.", while in the absence of ammonium, nitrate is reduced to nitrogen by "Candidatus Methylomirabilis oxyfera". Therefore, different co-cultures are dominated in a biological system depending on the availability of the nitrogen species (nitrate, nitrite or ammonium) (Haroon et al., 2013).
Potential strategies for the mainstream application of anammox in treatment of anaerobic effluents - A review
Published in Critical Reviews in Environmental Science and Technology, 2021
Khalid Muzamil Gani, Oluyemi Olatunji Awolusi, Abid Ali Khan, Sheena Kumari, Faizal Bux
Denitrifying anaerobic methane oxidation (DAMO) can be carried out by DAMO organisms, which oxidize methane anaerobically using nitrate or nitrite. The archaeon Candidatus Methanoperedens nitroreducens converts nitrate into nitrite using methane-derived electrons (Haroon et al., 2013) and the nitrite produced can be consumed by anammox thereby, reducing the limitations of nitrite availability. In contrast to it, there is another DAMO organism Candidatus Methylomirabilis oxyfera (M. oxyfera), which also oxidizes methane by using nitrite. Nitrite is reduced to nitric oxide and in situ oxygen produced during its dismutation to nitrogen gas help to achieve methane oxidation (Ettwig et al., 2010). Therefore, the coexistence of DAMO archaea and anammox bacteria in a co-enrichment culture can remove dissolved methane, ammonium, and nitrate simultaneously in wastewater treatment, making an anammox process more sustainable as there will be no requirement of extra carbon source for denitrification. Process stoichiometry in the system will be as per below reactions (van Kessel et al., 2018).
Integration of methane removal in aerobic anammox-based granular sludge reactors
Published in Environmental Technology, 2018
Celia M. Castro-Barros, Long T. Ho, Mari K. H. Winkler, Eveline I. P. Volcke
About a decade ago, it was found that anaerobic CH4 oxidation coupled to denitrification can take place [4]. Denitrifying anaerobic methane oxidation (damo) can be carried out by denitrifying anaerobic methane-oxidizing bacteria (damoB), namely Candidatus Methylomirabilis oxyfera, which couple CH4 oxidation to nitrite reduction [5,6] (Equation (1)) and by denitrifying anaerobic methanotrophic archaea (damoA), such as Candidatus Methanoperedens nitroreducens, that uses nitrate as an electron acceptor [7] (Equation (2)).Apart from its dissolved CH4 content, reject water is in the first place characterized by high nitrogen concentrations in the form of ammonium and by high temperatures, and is therefore suitable for the application of anaerobic ammonium oxidation (anammox) technology [8], implying important energy and chemical savings compared to conventional nitrogen removal over nitrate. Ammonium can be conveniently removed from reject water with a combined partial nitritation–anammox process [9,10], which can be implemented in one or two stages. Partial nitritation–anammox reactors have become widely applied at full-scale for the treatment of high-strength ammonium wastewaters [11]. A lot of research interest currently goes to their integration for mainstream treatment, following anaerobic psychrophilic treatment or an aerobic stage operated at a low sludge retention time [12,13].