title: Molecular diversity and distribution of aromatic hydrocarbon-degrading anaerobes across a landfill leachate plume.
abstract: Natural attenuation of the mono-aromates benzene, toluene, ethylbenzene and xylene occurs under iron-reducing conditions in a leachate-contaminated aquifer near the Banisveld landfill, the Netherlands. The diversity of mono-aromate-degrading microorganisms was studied by targeting functional genes encoding benzylsuccinate synthase α-subunit (bssA) and 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase (bamA). Sixty-four bssA and 188 bamA variants were sequenced from groundwater sampled along the pollution plume in 1999 and 2004. Species containing bssA sequences closest affiliated (> 91%) with the betaprotebacterium Georgfuchsia toluolica were the dominant alkylbenzene degraders (89% of bssA sequences). bssA genes were found at more than 10-fold lower copy numbers than bamA genes, of which only a small fraction (< 2%) was closely related to the genes of Georgfuchsia. bamA gene diversity was high and bamA-based community composition was primarily affected by dissolved organic carbon (DOC) and ferrous iron concentrations. bamA sequences closest related to Geobacteraceae were dominantly (43.2%) observed and the presence of Geobacteraceae-related bamA sequences was associated with DOC. Our results indicate a key role for specialized Georgfuchsia spp. in the degradation of alkylbenzenes, whereas Geobacteraceae are involved in degradation of aromatics other than toluene and xylene.
authors.affiliation: Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Staats
authors.forename: Martin
authors.initials: M
authors.lastname: Braster
authors.forename: Wilfred F M
authors.initials: WF
authors.lastname: Röling
mesh_terms: D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D019755:Carbon-Carbon Lyases / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D020564:Deltaproteobacteria / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D006867:Hydrolases / Q000235:genetics; D009426:Netherlands; D010802:Phylogeny; D012037:Refuse Disposal; D014867:Water / Q000032:analysis / Q000737:chemistry; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D006841:Hydrocarbons, Aromatic; D014874:Water Pollutants, Chemical; D014867:Water; D006867:Hydrolases; C120741:6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase; D019755:Carbon-Carbon Lyases; C114354:benzylsuccinate synthase