Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1021/acs.est.8b06643
Volltext Akzeptiertes Manuskript
Titel (primär) Mechanistic dichotomy in bacterial trichloroethene dechlorination revealed by carbon and chlorine isotope effects
Autor Lihl, C.; Douglas, L.M.; Franke, S.; Pérez-de-Mora, A.; Meyer, A.H.; Daubmeier, M.; Edwards, E.A.; Nijenhuis, I.; Sherwood Lollar, B.; Elsner, M.
Quelle Environmental Science & Technology
Erscheinungsjahr 2019
Department ISOBIO
Band/Volume 53
Heft 8
Seite von 4245
Seite bis 4254
Sprache englisch
Abstract Tetrachloroethene (PCE) and trichloroethene (TCE) are significant groundwater contaminants. Microbial reductive dehalogenation at contaminated sites can produce nontoxic ethene but often stops at toxic cis-1,2-dichloroethene (cis-DCE) or vinyl chloride (VC). The magnitude of carbon relative to chlorine isotope effects (as expressed by ΛC/Cl, the slope of δ13C versus δ37Cl regressions) was recently recognized to reveal different reduction mechanisms with vitamin B12 as a model reactant for reductive dehalogenase activity. Large ΛC/Cl values for cis-DCE reflected cob(I)alamin addition followed by protonation, whereas smaller ΛC/Cl values for PCE evidenced cob(I)alamin addition followed by Cl elimination. This study addressed dehalogenation in actual microorganisms and observed identical large ΛC/Cl values for cis-DCE (ΛC/Cl = 10.0 to 17.8) that contrasted with identical smaller ΛC/Cl for TCE and PCE (ΛC/Cl = 2.3 to 3.8). For TCE, the trend of small ΛC/Cl could even be reversed when mixed cultures were precultivated on VC or DCEs and subsequently confronted with TCE (ΛC/Cl = 9.0 to 18.2). This observation provides explicit evidence that substrate adaptation must have selected for reductive dehalogenases with different mechanistic motifs. The patterns of ΛC/Cl are consistent with practically all studies published to date, while the difference in reaction mechanisms offers a potential answer to the long-standing question of why bioremediation frequently stalls at cis-DCE.
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Lihl, C., Douglas, L.M., Franke, S., Pérez-de-Mora, A., Meyer, A.H., Daubmeier, M., Edwards, E.A., Nijenhuis, I., Sherwood Lollar, B., Elsner, M. (2019):
Mechanistic dichotomy in bacterial trichloroethene dechlorination revealed by carbon and chlorine isotope effects
Environ. Sci. Technol. 53 (8), 4245 - 4254 10.1021/acs.est.8b06643