Charakterisierung der mikrobiellen Dehalogenierung mittels substanzspezifischer Isotopenanalyse
Zusammenfassung der Projektergebnisse
Wichtigste Ergebnisse: The effect of intracellular microscale mass transfer on microbial carbon isotope fractionation of tetrachloroethene (PCE) and trichloroethene (TCE) was investigated. Conclusively, ratelimiting mass transfer barriers were (a) the outer membrane or cell wall and (b) the cytoplasmic membrane in case of a cytoplasmic location of the RDase enzyme. Overall, our results indicate that masking of isotope fractionation is determined by (1) hydrophobicity of the degraded compound, (2) properties of the cell envelope, and (3) the localization of the reacting enzyme. - The role of the corrinoid cofactor in reductive dehalogenation catalysis by tetrachloroethene reductive dehalogenase (PceA) of Sulfurospirillum multivorans was investigated using isotope analysis of carbon and chlorine. Our results suggest mechanistic and/or kinetic differences in catalytic PCE dehalogenation by enzymes and different corrinoids, whereas such differences were not observed for TCE. - The anaerobic transformation of 1,2-DCA by Dehalococcoides mccartyi strain 195 and strain BTF08 was analysed using triple-element compound-specific stable isotope analysis (CSIA) of carbon, chlorine and hydrogen for the first time. Isotope fractionation patterns for carbon and chlorine within both investigated D. mccartyi strains, as well as the dual-element analysis, supported identical reaction mechanisms for dehalogenation of 1,2-DCA. Hydrogen isotope fractionation analysis revealed dihaloelimination as prevalent reaction mechanism. - Proteomic analysis indicates that only PteA and VcrA are needed for the complete dehalogenation of PCE to ethene. TceA was induced in presence of 1,2-DCA, however not in presence of chlorinated ethenes. - A mechanistic dichotomy was detected for bacterial TCE dechlorination using dual-element carbon and chlorine analysis. Depending on cultivation conditions and microbial community present, the dechlorination reaction was proposed to run either via an initial Cl elimination with subsequent protonation or via an initial protonation with subsequent dechlorination. - For Dehalococcoides mccartyi strain BTF08, the reductive dechlorination of PCE was proposed to run via an initial Cl elimination while the initial step for VC and cis-DCE dechlorination was proposed to be a protonation step. The observation was independent of the reductive dehalogenases present. - Based on dual-element C/Cl stable isotope analysis, different patterns and presumably different reactions were concluded for dechlorination of 1,2-DCA in presence of VcrA or TceA, respectively. - A new LC/IRMS method for the quantitative determination of halogenated benzoates was developed. Characterisation of growth and carbon stable isotope analysis, suggested that dehalogenation of para-halobenzoic acids by Thauera chlorobenzoica strain 3CB-1T follows a different mechanism from that of meta-halobenzoic acids.
Projektbezogene Publikationen (Auswahl)
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2014. Combined C and Cl Isotope Effects Indicate Differences between Corrinoids and Enzyme (Sulfurospirillum multivorans PceA) in Reductive Dehalogenation of Tetrachloroethene, But Not Trichloroethene. Environ Sci Technol 48:11837-45
Renpenning J, Keller S, Cretnik S, Shouakar-Stash O, Elsner M, Schubert T, Nijenhuis I
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2015. Substrate hydrophobicity and cell composition influence the extent of rate limitation and masking of isotope fractionation during microbial reductive dehalogenation of chlorinated ethenes. Environ Sci Technol 49:4293-301
Renpenning J, Rapp I, Nijenhuis I
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2016. Anaerobic microbial dehalogenation of organohalides - state of the art and remediation strategies. Current Opinion in Biotechnology 38:33-38
Nijenhuis I, Kuntze K
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2016. Evaluation of the microbial reductive dehalogenation reaction using compound-specific stable isotope analysis (CSIA), p 429-453. In Adrian L, Löffler F (eds), Organohalide-Respiring Bacteria. Springer, Berlin Heidelberg
Renpenning J, Nijenhuis I
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2016. Recent advances in multielement compound-specific stable isotope analysis of organohalides: Achievements, challenges and prospects for assessing environmental sources and transformation. Trends in Environmental Analytical Chemistry 11:1-8
Nijenhuis I, Renpenning J, Kümmel S, Richnow HH, Gehre M
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2017. Triple-element compound-specific stable isotope analysis of 1,2-dichloroethane for characterization of the underlying dehalogenation reaction in two Dehalococcoides mccartyi strains. FEMS Microbiol Ecol 93:fix137
Franke S, Lihl C, Renpenning J, Elsner M, Nijenhuis I
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2018. Anaerobic microbial dehalogenation and its key players in the contaminated Bitterfeld-Wolfen megasite. FEMS Microbiol Ecol 94:fiy012
Nijenhuis I, Stollberg R, Lechner U
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2018. Liquid chromatography/isotope ratio mass spectrometry analysis of halogenated benzoates for characterization of the underlying degradation reaction in Thauera chlorobenzoica CB-1(T). Rapid Comm Mass Spec 32:906-912
Franke S, Kummel S, Nijenhuis I
