title: Stable carbon isotope fractionation during degradation of dichloromethane by methylotrophic bacteria.
abstract: Stable carbon isotope fractionation during dichloromethane (DCM) degradation by methylotrophic bacteria was investigated under aerobic and nitrate-reducing conditions. The strains studied comprise several Hyphomicrobium strains, Methylobacterium, Methylopila, Methylophilus and Methylorhabdus spp. that are considered to degrade DCM by a glutathione (GSH)-dependent dehalogenase enzyme system in the initial step. The stable carbon isotope fractionation factors (alphaC) of the strains varied under aerobic conditions between 1.043 and 1.071 and under nitrate-reducing conditions between 1.048 and 1.065. Comparison of isotope fractionation under aerobic and nitrate-reducing conditions by individual strains revealed only minor to no differences. The variability in isotope fractionation among strains was found to be related to the polymorphism of the functional genes encoding the DCM dehalogenase.
authors.affiliation: Department of Bioremediation, UFZ-Centre for Environmental Research Leipzig-Halle GmbH, Permoserstr. 15, D-04318 Leipzig, Germany.
authors.forename: Marcell
authors.initials: M
authors.lastname: Nikolausz
authors.forename: Ivonne
authors.initials: I
authors.lastname: Nijenhuis
authors.forename: Katja
authors.initials: K
authors.lastname: Ziller
authors.forename: Hans-Hermann
authors.initials: HH
authors.lastname: Richnow
authors.forename: Matthias
authors.initials: M
authors.lastname: Kästner
mesh_terms: D000332:Aerobiosis; D020561:Alphaproteobacteria / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000378:metabolism*; D005591:Chemical Fractionation; D002712:Chlorides / Q000032:analysis; D002849:Chromatography, Gas; D016000:Cluster Analysis; D008190:Lyases / Q000235:genetics; D008752:Methylene Chloride / Q000378:metabolism*; D008969:Molecular Sequence Data; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D002247:Carbon Isotopes; D002712:Chlorides; D009566:Nitrates; D009573:Nitrites; D008752:Methylene Chloride; D008190:Lyases; C045224:dichloromethane dehalogenase