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| Titel |
Studies on a Novel Actinobacteria Species Capable of Oxidizing Ammonium under Iron Reduction Conditions |
| VerfasserIn |
Shan Huanh, Melany Ruiz-Urigüen, Peter R. Jaffe |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090201
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| Publikation (Nr.) |
 EGU/EGU2014-4422.pdf |
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| Zusammenfassung |
| Ammonium (NH4+) oxidation coupled to iron reduction in the absence of oxygen and
nitrate/nitrite (NO3-/NO2-) was noted in a forested riparian wetland in New Jersey (1,2),
and in tropical rainforest soils (3), and was coined Feammox (4). Through a 180-days
anaerobic incubation of soil samples collected at the New Jersey site, and using 16S
rDNA PCR-DGGE, 454-pyosequecing, and qPCR analysis, we have shown that an
Acidimicrobiaceae bacterium A6, belonging to the phylum Actinobacteria, is responsible for
this Feammox process, described previously (1,2). We have enriched these Feammox bacteria
in a high efficiency Feammox membrane reactor (with 85% NH4+removal per 48h),
and isolated the pure Acidimicrobiaceae bacterium A6 strain 5, in an autotrophic
medium.
To determine if the Feammox bacteria found in this study are common, at least at the
regional scale, we analyzed a series of local wetland-, upland-, as well as storm-water
detention pond-sediments. Through anaerobic incubations and molecular biology analysis,
the Feammox reaction and Acidimicrobiaceae bacterium A6 were found in three of twenty
soil samples collected, indicating that the Feammox pathway might be widespread in selected
soil environments. Results show that soil pH and Fe(III) content are key environmental
factors controlling the distributions of Feammox bacteria, which require acidic conditions
and the presence of iron oxides. Results from incubation experiments conducted at
different temperatures have shown that, in contrast to another anaerobic ammonium
oxidation pathways (e.g., anammox), the optimal temperature of the Feammox process
is ~ 20° and that the organisms are still active when the temperature is around
10°.
An incubation experiment amended with acetylene gas (C2H2) as a selected inhibitor
showed that in the Feammox reaction, Fe(III) is the electron acceptor, which is reduced to
Fe(II), and NH4+is the electron donor, which is oxidized to NO2-. After this process,
NO2- is converted to nitrogen gas (N2) via conventional denitrification and/or
anammox.
Based on the results obtained so far, we conclude that Feammox may be an
important process for nitrogen loss in iron rich, acidic soil environments under
oxygen-limited conditions. Our results from operating a membrane reactor with a high
Acidimicrobiaceae bacterium A6 content (~ 50%) indicate that it might be possible to
develop a novel anaerobic NH4+ removal technology from wastewater based on the
Feammox process, which might be more robust at low temperatures than Anammox-based
processes.
References
1. Clement J.C., Shrestha J., Ehrenfeld J.G., Jaffé P.R., 2005. Soil Biol Biochem
37:2323–2328.
2. Shrestha J., Rich J., Ehrenfeld J., Jaffé P.R., 2009. Soil Sci. 174:156–164.
3. Sawayama S., 2006. J Biosci Bioeng 101:70–72.
4. Yang WH, Weber KA, Silver WL, 2012. Nat Geosc 5: 538–541.
5. Huang, S., and P.R. Jaffe, 2013. Mineralogical Magazine, 77(5): 1339. |
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