Editor: Alfons Stams
Dominance of Geobacteraceae in BTX-degrading enrichments from an iron-reducing aquifer
Article first published online: 3 SEP 2007
FEMS Microbiology Ecology
Volume 62, Issue 1, pages 118–130, October 2007
How to Cite
Botton, S., Van Harmelen, M., Braster, M., Parsons, J. R. and Röling, W. F.M. (2007), Dominance of Geobacteraceae in BTX-degrading enrichments from an iron-reducing aquifer. FEMS Microbiology Ecology, 62: 118–130. doi: 10.1111/j.1574-6941.2007.00371.x
- Issue published online: 28 SEP 2007
- Article first published online: 3 SEP 2007
- Received 13 November 2006; revised 15 June 2007; accepted 21 June 2007.First published online September 2007.
Microbial community structure was linked to degradation potential in benzene-, toluene- or xylene- (BTX) degrading, iron-reducing enrichments derived from an iron-reducing aquifer polluted with landfill leachate. Enrichments were characterized using 16S rRNA gene-based analysis, targeting of the benzylsuccinate synthase-encoding bssA gene and phospholipid fatty acid (PLFA) profiling in combination with tracking of labelled substrate. 16S rRNA gene analysis indicated the dominance of Geobacteraceae, and one phylotype in particular, in all enrichments inoculated with polluted aquifer material. Upon cultivation, progressively higher degradation rates with a concomitant decrease in species richness occurred in all primary incubations and successive enrichments. Yet, the same Geobacteraceae phylotype remained common and dominant, indicating its involvement in BTX degradation. However, the bssA gene sequences in BTX degrading enrichments differed considerably from those of Geobacter isolates, suggesting that the first steps of toluene, but also benzene and xylene oxidation, are carried out by another member of the enrichments. Therefore, BTX would be synthrophically degraded by a bacterial consortium in which Geobacteraceae utilized intermediate metabolites. PLFA analysis in combination with 13C-toluene indicated that the enriched Geobacteraceae were assimilating carbon originally present in toluene. Combined with previous studies, this research suggests that Geobacteraceae play a key role in the natural attenuation of each BTX compound in situ.