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Electron acceptor-dependent identification of key anaerobic toluene degraders at a tar-oil-contaminated aquifer by Pyro-SIP.

FEMS Microbiol. Ecol. 78, 165-175 (2011)
Open Access Green as soon as Postprint is submitted to ZB.
Bioavailability of electron acceptors is probably the most limiting factor in the restoration of anoxic, contaminated environments. The oxidation of contaminants such as aromatic hydrocarbons, particularly in aquifers, often depends on the reduction of ferric iron or sulphate. We have previously detected a highly active fringe zone beneath a toluene plume at a tar-oil-contaminated aquifer in Germany, where a specialized community of contaminant degraders codominated by Desulfobulbaceae and Geobacteraceae had established. Although on-site geochemistry links degradation to sulphidogenic processes, dominating catabolic (benzylsuccinate synthase α-subunit, bssA) genes detected in situ appeared to be more related to those of Geobacter spp. Therefore, a stable isotope probing (SIP) incubation of sediment samples with (13) C(7) -toluene and comparative electron acceptor amendment was performed. We introduce pyrosequencing of templates from SIP microcosms as a powerful new strategy in SIP gradient interpretation (Pyro-SIP). Our results reveal the central role of Desulfobulbaceae in sulphidogenic toluene degradation in situ, and affiliate the detected bssA genes to this lineage. This and the absence of (13) C-labelled DNA of Geobacter spp. in SIP gradients preclude their relevance as toluene degraders in situ. In contrast, Betaproteobacteria related to Georgfuchsia spp. became labelled under iron-reducing conditions. Furthermore, secondary toluene degraders belonging to the Peptococcaceae detected in both treatments suggest the possibility of functional redundancy among anaerobic toluene degraders on site.
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Publication type Article: Journal article
Document type Scientific Article
Keywords stable isotope probing; groundwater natural attenuation; sulphate and iron reduction; amplicon pyrosequencing; benzylsuccinate synthase (bssA)
ISSN (print) / ISBN 0168-6496
e-ISSN 1574-6941
Quellenangaben Volume: 78, Issue: 1, Pages: 165-175 Article Number: , Supplement: ,
Publisher Wiley
Publishing Place Oxford
Reviewing status Peer reviewed