Palau, JordiTrueba-Santiso, AlbaYu, R.Mortan, SShouakar-Stash, OFreedman, D.L.Wasmund, K.Hunkeler, D.Marco-Urrea, E.Rosell Linares, Mònica2023-03-162023-03-162023-01-260013-936Xhttps://hdl.handle.net/2445/195361Brominated organic compounds such as 1,2-dibromoethane (1,2-DBA) are highly toxic groundwater contaminants. Multi-element compound-specific isotope analysis bears the potential to elucidate the biodegradation pathways of 1,2-DBA in the environment, which is crucial information to assess its fate in contaminated sites. This study investigates for the first time dual C−Br isotope fractionation during in vivo biodegradation of 1,2-DBA by two anaerobic enrichment cultures containing organohaliderespiring bacteria (i.e., either Dehalococcoides or Dehalogenimonas). Different εbulk C values (−1.8 ± 0.2 and −19.2 ± 3.5¿, respectively) were obtained, whereas their respective εbulk Br values were lower and similar to each other (−1.22 ± 0.08 and −1.2 ± 0.5¿), leading to distinctly different trends (ΛC−Br = Δδ13C/Δδ81Br ≈ εbulkC /εbulkBr ) in a dual C−Br isotope plot (1.4 ± 0.2 and 12 ± 4, respectively). These results suggest the occurrence of different underlying reaction mechanisms during enzymatic 1,2-DBA transformation, that is, concerted dihaloelimination and nucleophilic substitution (SN2-reaction). The strongly pathway-dependent ΛC−Br values illustrate the potential of this approach to elucidate the reaction mechanism of 1,2-DBA in the field and to select appropriate εbulkC values for quantification of biodegradation. The results of this study provide valuable information for future biodegradation studies of 1,2-DBA in contaminated sites.10 p.application/pdfeng(c) The Authors , 2023http://creativecommons.org/licenses/by/3.0/es/BiodegradacióIsòtops de carboniIsòtopsBiodegradationCarbon isotopesIsotopesinfo:eu-repo/semantics/article7324882023-03-16info:eu-repo/semantics/openAccess