TY - JOUR
T1 - Carbon and nitrogen isotope effects associated with the dioxygenation of aniline and diphenylamine
AU - Pati, Sarah G.
AU - Shin, Kwanghee
AU - Skarpeli-Liati, Marita
AU - Bolotin, Jakov
AU - Eustis, Soren N.
AU - Spain, Jim C.
AU - Hofstetter, Thomas B.
PY - 2012/11/6
Y1 - 2012/11/6
N2 - Dioxygenation of aromatic rings is frequently the initial step of biodegradation of organic subsurface pollutants. This process can be tracked by compound-specific isotope analysis to assess the extent of contaminant transformation, but the corresponding isotope effects, especially for dioxygenation of N-substituted, aromatic contaminants, are not well understood. We investigated the C and N isotope fractionation associated with the biodegradation of aniline and diphenylamine using pure cultures of Burkholderia sp. strain JS667, which can biodegrade both compounds, each by a distinct dioxygenase enzyme. For diphenylamine, the C and N isotope enrichment was normal with εC- and εN-values of -0.6 ± 0.1% and -1.0 ± 0.1%, respectively. In contrast, N isotopes of aniline were subject to substantial inverse fractionation (εN of +13 ± 0.5%), whereas the εC-value was identical to that of diphenylamine. A comparison of the apparent kinetic isotope effects for aniline and diphenylamine dioxygenation with those from abiotic oxidation by manganese oxide (MnO2) suggest that the oxidation of a diarylamine system leads to distinct C-N bonding changes compared to aniline regardless of reaction mechanism and oxidant involved. Combined evaluation of the C and N isotope signatures of the contaminants reveals characteristic δδ 15N/δδ13C-trends for the identification of diphenylamine and aniline oxidation in contaminated subsurfaces and for the distinction of aniline oxidation from its formation by microbial and/or abiotic reduction of nitrobenzene.
AB - Dioxygenation of aromatic rings is frequently the initial step of biodegradation of organic subsurface pollutants. This process can be tracked by compound-specific isotope analysis to assess the extent of contaminant transformation, but the corresponding isotope effects, especially for dioxygenation of N-substituted, aromatic contaminants, are not well understood. We investigated the C and N isotope fractionation associated with the biodegradation of aniline and diphenylamine using pure cultures of Burkholderia sp. strain JS667, which can biodegrade both compounds, each by a distinct dioxygenase enzyme. For diphenylamine, the C and N isotope enrichment was normal with εC- and εN-values of -0.6 ± 0.1% and -1.0 ± 0.1%, respectively. In contrast, N isotopes of aniline were subject to substantial inverse fractionation (εN of +13 ± 0.5%), whereas the εC-value was identical to that of diphenylamine. A comparison of the apparent kinetic isotope effects for aniline and diphenylamine dioxygenation with those from abiotic oxidation by manganese oxide (MnO2) suggest that the oxidation of a diarylamine system leads to distinct C-N bonding changes compared to aniline regardless of reaction mechanism and oxidant involved. Combined evaluation of the C and N isotope signatures of the contaminants reveals characteristic δδ 15N/δδ13C-trends for the identification of diphenylamine and aniline oxidation in contaminated subsurfaces and for the distinction of aniline oxidation from its formation by microbial and/or abiotic reduction of nitrobenzene.
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U2 - 10.1021/es303043t
DO - 10.1021/es303043t
M3 - Article
C2 - 23017098
AN - SCOPUS:84868526214
SN - 0013-936X
VL - 46
SP - 11844
EP - 11853
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 21
ER -