TY - JOUR
T1 - Trichloromethane dechlorination by a novel Dehalobacter sp. strain 8M reveals a third contrasting C and Cl isotope fractionation pattern within this genus
AU - Soder-Walz, Jesica M.
AU - Torrentó, Clara
AU - Algora, Camelia
AU - Wasmund, Kenneth
AU - Cortés, Pilar
AU - Soler, Albert
AU - Vicent, Teresa
AU - Rosell, Mònica
AU - Marco-Urrea, Ernest
N1 - Funding Information:
This work has been supported by the Spanish Ministry of Economy and Competitiveness State Research Agency ( CTM2016-75587-C2-1-R , PID2019-103989RB-100 and CGL2017-87216-C4-1-R projects) cofinanced by the European Union through the European Regional Development Fund (ERDF). This work was partly supported by the Generalitat de Catalunya (Consolidate Research Groups 2017-SGR-14 and 2017-SGR-1733 ). We thank Angie Steffany Albarracín and Natàlia Blázquez Pallí for their collaboration in this project and CCiT-UB for the technical support.
Publisher Copyright:
© 2021 The Authors
PY - 2022/3/20
Y1 - 2022/3/20
N2 - Trichloromethane (TCM) is a pollutant frequently detected in contaminated aquifers, and only four bacterial strains are known to respire it. Here, we obtained a novel Dehalobacter strain capable of transforming TCM to dichloromethane, which was denominated Dehalobacter sp. strain 8M. Besides TCM, strain 8M also completely transformed 1,1,2-trichloroethane to vinyl chloride and 1,2-dichloroethane. Quantitative PCR analysis for the 16S rRNA genes confirmed growth of Dehalobacter with TCM and 1,1,2-trichloroethane as electron acceptors. Carbon and chlorine isotope fractionation during TCM transformation was studied in cultured cells and in enzymatic assays with cell suspensions and crude protein extracts. TCM transformation in the three studied systems resulted in small but significant carbon (εC = −2.7 ± 0.1‰ for respiring cells, −3.1 ± 0.1‰ for cell suspensions, and − 4.1 ± 0.5‰ for crude protein extracts) and chlorine (εCl = −0.9 ± 0.1‰, −1.1 ± 0.1‰, and − 1.2 ± 0.2‰, respectively) isotope fractionation. A characteristic and consistent dual C[sbnd]Cl isotope fractionation pattern was observed for the three systems (combined ΛC/Cl = 2.8 ± 0.3). This ΛC/Cl differed significantly from previously reported values for anaerobic dechlorination of TCM by the corrinoid cofactor vitamin B12 and other Dehalobacter strains. These findings widen our knowledge on the existence of different enzyme binding mechanisms underlying TCM-dechlorination within the genus Dehalobacter and demonstrates that dual isotope analysis could be a feasible tool to differentiate TCM degraders at field studies.
AB - Trichloromethane (TCM) is a pollutant frequently detected in contaminated aquifers, and only four bacterial strains are known to respire it. Here, we obtained a novel Dehalobacter strain capable of transforming TCM to dichloromethane, which was denominated Dehalobacter sp. strain 8M. Besides TCM, strain 8M also completely transformed 1,1,2-trichloroethane to vinyl chloride and 1,2-dichloroethane. Quantitative PCR analysis for the 16S rRNA genes confirmed growth of Dehalobacter with TCM and 1,1,2-trichloroethane as electron acceptors. Carbon and chlorine isotope fractionation during TCM transformation was studied in cultured cells and in enzymatic assays with cell suspensions and crude protein extracts. TCM transformation in the three studied systems resulted in small but significant carbon (εC = −2.7 ± 0.1‰ for respiring cells, −3.1 ± 0.1‰ for cell suspensions, and − 4.1 ± 0.5‰ for crude protein extracts) and chlorine (εCl = −0.9 ± 0.1‰, −1.1 ± 0.1‰, and − 1.2 ± 0.2‰, respectively) isotope fractionation. A characteristic and consistent dual C[sbnd]Cl isotope fractionation pattern was observed for the three systems (combined ΛC/Cl = 2.8 ± 0.3). This ΛC/Cl differed significantly from previously reported values for anaerobic dechlorination of TCM by the corrinoid cofactor vitamin B12 and other Dehalobacter strains. These findings widen our knowledge on the existence of different enzyme binding mechanisms underlying TCM-dechlorination within the genus Dehalobacter and demonstrates that dual isotope analysis could be a feasible tool to differentiate TCM degraders at field studies.
KW - 1,1,2-trichloroethane
KW - 2D-CSIA
KW - Dehalobacter
KW - Isotopic fractionation
KW - Organohalide respiration
KW - Trichloromethane
UR - http://www.scopus.com/inward/record.url?scp=85121909144&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2021.152659
DO - 10.1016/j.scitotenv.2021.152659
M3 - Article
C2 - 34954170
AN - SCOPUS:85121909144
SN - 0048-9697
VL - 813
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 152659
ER -