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| Titel |
Isotopomeric characterization of nitrous oxide produced by reaction of enzymes extracted from nitrifying and denitrifying bacteria |
| VerfasserIn |
T. Yamazaki, T. Hozuki, K. Arai, S. Toyoda, K. Koba, T. Fujiwara, N. Yoshida |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 10 ; Nr. 11, no. 10 (2014-05-21), S.2679-2689 |
| Datensatznummer |
250117417
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| Publikation (Nr.) |
 copernicus.org/bg-11-2679-2014.pdf |
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| Zusammenfassung |
| Nitrous oxide (N2O) is a potent greenhouse gas and produced in
denitrification and nitrification by various microorganisms. Site preference
(SP) of 15N in N2O, which is defined as the difference in the
natural abundance of isotopomers 14N15NO and 15N14NO
relative to 14N14NO, has been reported to be a useful tool to
quantitatively distinguish N2O production pathways. To determine
representative SP values for each microbial process, we firstly measured SP
of N2O produced in the enzyme reaction of hydroxylamine oxidoreductase
(HAO) purified from two species of ammonia oxidizing bacteria (AOB),
Nitrosomonas europaea and Nitrosococcus oceani, and that of
nitric oxide reductase (NOR) from Paracoccus denitrificans. The SP
value for NOR reaction (−5.9 ± 2.1‰) showed nearly the same
value as that reported for N2O produced by P. denitrificans in
pure culture. In contrast, SP value for HAO reaction
(36.3 ± 2.3‰) was a little higher than the values reported
for N2O produced by AOB in aerobic pure culture. Using the SP values
obtained by HAO and NOR reactions, we calculated relative contribution of the
nitrite (NO2–) reduction (which is followed by NO reduction) to
N2O production by N. oceani incubated under different O2
availability. Our calculations revealed that previous in vivo studies might
have underestimated the SP value for the NH2OH oxidation pathway
possibly due to a small contribution of NO2– reduction pathway.
Further evaluation of isotopomer signatures of N2O using common enzymes
of other processes related to N2O would improve the isotopomer analysis
of N2O in various environments. |
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