TY  - JOUR
AU  - Meyer, A.
AU  - Bergmann, J.
AU  - Butterbach-Bahl, K.
AU  - Brüggemann, N.
TI  - A new 15N tracer method to determine N turnover and denitrification of Pseudomonas stutzeri
JO  - Isotopes in Environmental and Health Studies
VL  - 46
SN  - 1025-6016
CY  - London [u.a.]
PB  - Taylor and Francis
M1  - PreJuSER-15171
SP  - 409 - 421
PY  - 2010
N1  - This work was funded by the Deutsche Forschungsgemeinschaft (DFG) within the Beech Research Group (FOR 788), the EU-funded integrated project NitroEurope and by the Joint Helmholtz/Chinese Academy of Sciences Laboratory ENTRANCE.
AB  - Although denitrification is one of the key processes of ecosystem N turnover, the understanding of the regulation of the denitrification pathway is still limited due to the lack of feasible methods for the quantification of N₂ formation. Based on the previously developed isotope pairing method, we present a new in vitro ¹⁵N tracer method for the quantification of N₂ released from denitrification by bacterial cultures. The application of the new method was enabled by replacing the background air in the sample flasks with a gas mixture of He and O₂ with an approximately 50-fold reduced N₂ background (1.7% v/v), allowing for a direct and sensitive quantification of N₂ formation with isotope-ratio mass spectrometry after ¹⁵N-labelling on the one hand, but leaving the method relatively insensitive to intrusion of ambient N₂ on the other hand. The method was tested on bacterial cultures of Pseudomonas stutzeri grown at different oxygen levels. Additionally, NO and N₂O formation were determined with a chemoluminescence analyser and a gas chromatograph, respectively. Following labelling with ¹⁵N-ammonium and ¹⁵N-nitrate, it could be shown that P. stutzeri used ammonium preferably for biomass build-up, and nitrate preferably as electron acceptor. Between 84-107% of the total available N could be recovered. Due to the high sensitivity of the new method only low levels of ¹⁵N tracer were necessary, minimising substrate-induced effects and making this method also an appropriate tool for the use on soil cores. By that it offers a new method for studying denitrification in terrestrial ecosystems.
KW  - Denitrification
KW  - Nitrogen Isotopes: metabolism
KW  - Pseudomonas stutzeri: metabolism
KW  - Nitrogen Isotopes (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:21058101
UR  - <Go to ISI:>//WOS:000285149100002
DO  - DOI:10.1080/10256016.2010.528840
UR  - https://juser.fz-juelich.de/record/15171
ER  -