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Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Nitrification and anammox with urea as the energy source
A Olav Sliekers1, Suzanne Haaijer, Markus Schmid
1Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
Systematic and Applied Microbiology
|June 25, 2004
Summary
Ammonia oxidizing bacteria (AOB) can utilize urea as an energy source, leading to direct conversion to dinitrogen gas. This study investigated urea utilization by AOB and anaerobic ammonia oxidizing (Anammox) bacteria using molecular methods.
Area of Science:
- Environmental microbiology
- Bacteriology
- Biogeochemical cycles
Background:
- Urea is an abundant ecosystem component and potential energy source.
- Ammonia oxidizing bacteria (AOB) and anaerobic ammonia oxidizing (Anammox) bacteria are key players in nitrogen cycling.
Purpose of the Study:
- To investigate urea utilization by AOB and Anammox bacteria.
- To compare urea and ammonia as substrates for these bacterial groups.
- To characterize the microbial communities involved in urea conversion.
Main Methods:
- Enrichment cultures inoculated with activated sludge.
- Molecular ecological methods including fluorescence in situ hybridization (FISH).
- PCR amplification, cloning, and phylogenetic analysis of amoA and 16S rRNA genes.
Main Results:
- Batch cultures with urea enriched for AOB, including Nitrosomonas oligotropha, Nitrosomonas europaea, and Nitrosomonas nitrosa.
- Under oxygen limitation, N. oligotropha-like AOB dominated urea-fed continuous cultures.
- Urea was directly converted to dinitrogen gas by AOB without organic carbon addition.
Conclusions:
- AOB can effectively utilize urea as an energy source.
- Specific AOB species dominate under urea-rich conditions, especially under oxygen limitation.
- This pathway facilitates direct urea conversion to dinitrogen gas in ecosystems.
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