Trichloromethane dechlorination by a novel Dehalobacter sp. strain 8M reveals a third contrasting C and Cl isotope fractionation pattern within this genus.

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  • Additional Information
    • Source:
      Publisher: Elsevier Country of Publication: Netherlands NLM ID: 0330500 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-1026 (Electronic) Linking ISSN: 00489697 NLM ISO Abbreviation: Sci Total Environ Subsets: MEDLINE
    • Publication Information:
      Original Publication: Amsterdam, Elsevier.
    • Subject Terms:
      Chloroform* ; Groundwater*; Biodegradation, Environmental ; Carbon Isotopes/analysis ; Chemical Fractionation ; RNA, Ribosomal, 16S/genetics
    • Abstract:
      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 (ε C  = -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 (ε Cl  = -0.9 ± 0.1‰, -1.1 ± 0.1‰, and - 1.2 ± 0.2‰, respectively) isotope fractionation. A characteristic and consistent dual CCl isotope fractionation pattern was observed for the three systems (combined Λ C/Cl  = 2.8 ± 0.3). This Λ C/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.
      Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
      (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)
    • Contributed Indexing:
      Keywords: 1,1,2-trichloroethane; 2D-CSIA; Dehalobacter; Isotopic fractionation; Organohalide respiration; Trichloromethane
    • Accession Number:
      0 (Carbon Isotopes)
      0 (RNA, Ribosomal, 16S)
      7V31YC746X (Chloroform)
    • Publication Date:
      Date Created: 20211226 Date Completed: 20220208 Latest Revision: 20220208
    • Publication Date:
      20240104
    • Accession Number:
      10.1016/j.scitotenv.2021.152659
    • Accession Number:
      34954170