TY - JOUR
T1 - Triple-element compound-specific stable isotope analysis of 1,2-dichloroethane for characterization of the underlying dehalogenation reaction in two Dehalococcoides mccartyi strains
AU - Franke, Steffi
AU - Lihl, Christina
AU - Renpenning, Julian
AU - Elsner, Martin
AU - Nijenhuis, Ivonne
N1 - Publisher Copyright:
© 2017 FEMS 2017. All rights reserved. For permissions, please e-mail: [email protected].
PY - 2017/12/1
Y1 - 2017/12/1
N2 - Chlorinated ethanes belong to the most common groundwater and soil contaminants. Of these, 1,2-dichloroethane (1,2-DCA) is a man-made, persistent and toxic contaminant, released due to improper waste treatment at versatile production sites. This study investigated the anaerobic transformation of 1,2-DCA by Dehalococcoides mccartyi strain 195 and strain BTF08 using triple-element compound-specific stable isotope analysis of carbon, chlorine and hydrogen for the first time. Isotope fractionation patterns for carbon (ϵCBTF08 =-28.4 ± 3.7‰; ϵC195 =-30.9 ± 3.6‰) and chlorine (ϵClBTF08 =-4.6 ± 0.7‰; ϵCl195 =-4.2 ± 0.5‰) within both investigated D. mccartyi strains, as well as the dual-element analysis (ΛBTF08 = 6.9 ± 1.2; Λ195 = 7.1 ± 0.2), supported identical reaction mechanisms for dehalogenation of 1,2-DCA. Hydrogen isotope fractionation analysis revealed dihaloelimination as prevalent reaction mechanism. Vinyl chloride as major intermediate could be excluded by performing the experiment in deuterated aqueous media. Furthermore, evaluation of the derived apparent kinetic isotope effects (AKIECBTF08 = 1.029/AKIEC195 = 1.031; AKIEClBTF08 = 1.005/AKIECl195 = 1.004) pointed towards simultaneous abstraction of both involved chlorine-substituents in a concerted matter. It was shown that D. mccartyi strain BTF08 and strain 195 are capable of complete, direct dihaloelimination of 1,2-DCA to ethene.
AB - Chlorinated ethanes belong to the most common groundwater and soil contaminants. Of these, 1,2-dichloroethane (1,2-DCA) is a man-made, persistent and toxic contaminant, released due to improper waste treatment at versatile production sites. This study investigated the anaerobic transformation of 1,2-DCA by Dehalococcoides mccartyi strain 195 and strain BTF08 using triple-element compound-specific stable isotope analysis of carbon, chlorine and hydrogen for the first time. Isotope fractionation patterns for carbon (ϵCBTF08 =-28.4 ± 3.7‰; ϵC195 =-30.9 ± 3.6‰) and chlorine (ϵClBTF08 =-4.6 ± 0.7‰; ϵCl195 =-4.2 ± 0.5‰) within both investigated D. mccartyi strains, as well as the dual-element analysis (ΛBTF08 = 6.9 ± 1.2; Λ195 = 7.1 ± 0.2), supported identical reaction mechanisms for dehalogenation of 1,2-DCA. Hydrogen isotope fractionation analysis revealed dihaloelimination as prevalent reaction mechanism. Vinyl chloride as major intermediate could be excluded by performing the experiment in deuterated aqueous media. Furthermore, evaluation of the derived apparent kinetic isotope effects (AKIECBTF08 = 1.029/AKIEC195 = 1.031; AKIEClBTF08 = 1.005/AKIECl195 = 1.004) pointed towards simultaneous abstraction of both involved chlorine-substituents in a concerted matter. It was shown that D. mccartyi strain BTF08 and strain 195 are capable of complete, direct dihaloelimination of 1,2-DCA to ethene.
KW - 1,2-dichloroethane
KW - Dehalococcoides
KW - compound-specific stable isotope analysis
KW - dihaloelimination
KW - reductive dehalogenation
UR - http://www.scopus.com/inward/record.url?scp=85043516456&partnerID=8YFLogxK
U2 - 10.1093/femsec/fix137
DO - 10.1093/femsec/fix137
M3 - Article
C2 - 29069488
AN - SCOPUS:85043516456
SN - 0168-6496
VL - 93
JO - FEMS Microbiology Ecology
JF - FEMS Microbiology Ecology
IS - 12
M1 - fix137
ER -