Dual C-Br isotope fractionation indicates distinct reductive dehalogenation mechanisms of 1,2-dibromoethane in dehalococcoides - and dehalogenimonas -containing cultures
Palau Capdevila, Jordi (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Trueba-Santiso, Alba (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Yu, Rong (Synterra Corporation)
Mortan, Siti Hatijah (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Shouakar-Stash, Orfan (Isotope Tracer Technologies Inc.)
Freedman, David L. (Clemson University. Department of Environmental Engineering and Earth Sciences)
Wasmund, Kenneth (University of Vienna. Centre for Microbiology and Environmental Systems Science. Division of Microbial Ecology)
Hunkeler, Daniel (University of Neuchâtel. Centre for Hydrogeology and Geothermics)
Marco Urrea, Ernest (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Rosell, Mònica (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)

Data:	2023
Resum:	Brominated 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 organohalide-respiring bacteria (i. e. , either Dehalococcoides or Dehalogenimonas). Different ε C values (−1. 8 ± 0. 2 and −19. 2 ± 3. 5‰, respectively) were obtained, whereas their respective ε Br values were lower and similar to each other (−1. 22 ± 0. 08 and −1. 2 ± 0. 5‰), leading to distinctly different trends (Λ = Δδ 13 C/Δδ 81 Br ≈ ε C /ε Br) 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 (S2-reaction). The strongly pathway-dependent Λ values illustrate the potential of this approach to elucidate the reaction mechanism of 1,2-DBA in the field and to select appropriate ε C values for quantification of biodegradation. The results of this study provide valuable information for future biodegradation studies of 1,2-DBA in contaminated sites. New insights into the reaction mechanisms of microbial reductive dehalogenation of brominated ethanes and information relevant to the application of CSIA in field studies.
Ajuts:	Ministerio de Ciencia e Innovación PID2019-103989RB-100 Ministerio de Economía y Competitividad CGL2017-82331-R Ministerio de Economía y Competitividad BES-2014-070817 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1733
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Brominated organic compounds ; Groundwater contamination ; Biodegradation ; Organohalide-respiring bacteria ; Compound-specific isotope analysis
Publicat a:	Environmental Science & Technology, Vol. 57, issue 5 (Feb. 2023) , p. 1949-1958, ISSN 1520-5851

DOI: 10.1021/acs.est.2c07137
PMID: 36700533

10 p, 3.1 MB

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