Isolation and characterization of Magnetospirillum sp strain 15-1 as a representative anaerobic toluene-degrader from a constructed wetland model

Ingrid Meyer-Cifuentes, Paula Maria Martinez Lavanchy, Vianey Marin-Cevada, Stefanie Boehnke, Hauke Harms, Jochen A. Mueller, Hermann J. Heipieper, Ivan A. Berg (Editor)

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    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 nitratereducing 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.
    Original languageEnglish
    JournalP L o S One
    Volume12
    Issue number4
    Number of pages16
    ISSN1932-6203
    DOIs
    Publication statusPublished - 2017

    Cite this

    Meyer-Cifuentes, I., Lavanchy, P. M. M., Marin-Cevada, V., Boehnke, S., Harms, H., Mueller, J. A., Heipieper, H. J., & Berg, I. A. (Ed.) (2017). Isolation and characterization of Magnetospirillum sp strain 15-1 as a representative anaerobic toluene-degrader from a constructed wetland model. P L o S One, 12(4). https://doi.org/10.1371/journal.pone.0174750