title: Isolation and characterization of Magnetospirillum sp. strain 15-1 as a representative anaerobic toluene-degrader from a constructed wetland model.
abstract: Previously, Planted Fixed-Bed Reactors (PFRs) have been used to investigate microbial toluene removal in the rhizosphere of constructed wetlands. Aerobic toluene degradation was predominant in these model systems although bulk redox conditions were hypoxic to anoxic. However, culture-independent approaches indicated also that microbes capable of anaerobic toluene degradation were abundant. Therefore, we aimed at isolating anaerobic-toluene degraders from one of these PFRs. From the obtained colonies which consisted of spirilli-shaped bacteria, a strain designated 15-1 was selected for further investigations. Analysis of its 16S rRNA gene revealed greatest similarity (99%) with toluene-degrading Magnetospirillum sp. TS-6. Isolate 15-1 grew with up to 0.5 mM of toluene under nitrate-reducing conditions. Cells reacted to higher concentrations of toluene by an increase in the degree of saturation of their membrane fatty acids. Strain 15-1 contained key genes for the anaerobic degradation of toluene via benzylsuccinate and subsequently the benzoyl-CoA pathway, namely bssA, encoding for the alpha subunit of benzylsuccinate synthase, bcrC for subunit C of benzoyl-CoA reductase and bamA for 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase. Finally, most members of a clone library of bssA generated from the PFR had highest similarity to bssA from strain 15-1. Our study provides insights about the physiological capacities of a strain of Magnetospirillum isolated from a planted system where active rhizoremediation of toluene is taking place.
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Meyer-Cifuentes
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.|Technical University of Denmark, Bibliometrics and Data Management, Department for Innovation and Sector Services, Lyngby, Denmark.
authors.forename: Paula M
authors.initials: PM
authors.lastname: Martinez-Lavanchy
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.
authors.forename: Vianey
authors.initials: V
authors.lastname: Marin-Cevada
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Böhnke
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Microbiology, Leipzig, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Harms
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.
authors.forename: Jochen A
authors.initials: JA
authors.lastname: Müller
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany.
authors.forename: Hermann J
authors.identifier: http://orcid.org/0000-0002-3723-9600
authors.initials: HJ
authors.lastname: Heipieper
mesh_terms: D002244:Carbon / Q000378:metabolism; D019755:Carbon-Carbon Lyases / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D042201:Magnetospirillum / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology; D014050:Toluene / Q000378:metabolism* / Q000633:toxicity; D014871:Water Microbiology; D053833:Wetlands
chemical_list: D005227:Fatty Acids; D008563:Membrane Lipids; D009566:Nitrates; D012336:RNA, Ribosomal, 16S; D014050:Toluene; D002244:Carbon; D019755:Carbon-Carbon Lyases; C114354:benzylsuccinate synthase; D010100:Oxygen