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Sci Rep. 2017 Dec 5;7(1):17028. doi: 10.1038/s41598-017-17312-2.

Investigation of different nitrogen reduction routes and their key microbial players in wood chip-driven denitrification beds.

Author information

1
Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
2
Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.
3
German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Braunschweig, Germany.
4
Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. johannes.gescher@kit.edu.
5
Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany. johannes.gescher@kit.edu.

Abstract

Field denitrification beds containing polymeric plant material are increasingly used to eliminate nitrate from agricultural drainage water. They mirror a number of anoxic ecosystems. However, knowledge of the microbial composition, the interaction of microbial species, and the carbon degradation processes within these denitrification systems is sparse. This study revealed several new aspects of the carbon and nitrogen cycle, and these findings can be correlated with the dynamics of the microbial community composition and the activity of key species. Members of the order Pseudomonadales seem to be important players in denitrification at low nitrate concentrations, while a switch to higher nitrate concentrations seems to select for members of the orders Rhodocyclales and Rhizobiales. We observed that high nitrate loading rates lead to an unpredictable transition of the community's activity from denitrification to dissimilatory reduction of nitrate to ammonium (DNRA). This transition is mirrored by an increase in transcripts of the nitrite reductase gene nrfAH and the increase correlates with the activity of members of the order Ignavibacteriales. Denitrification reactors sustained the development of an archaeal community consisting of members of the Bathyarchaeota and methanogens belonging to the Euryarchaeota. Unexpectedly, the activity of the methanogens positively correlated with the nitrate loading rates.

PMID:
29208961
PMCID:
PMC5716999
DOI:
10.1038/s41598-017-17312-2
[Indexed for MEDLINE]
Free PMC Article

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