Bacterial Community Dynamics in a Biofilter exposed to a Micropollutant

Perfluorooctanoic acid (PFOA) is a fluorinated compound used in many industrial and consumer products. It is environmentally persistent, widespread and bioaccumulative, and multiple toxicities have been reported in experimental models and wildlife. Trace amounts of PFOA have been detected in humans, animals and numerous environmental compartments, including drinking water sources. PFOA can be removed from drinking water by technically complex and energy intensive treatment processes. If the target compound is biodegradable, biological filtration could be a suitable alternative for removal of the contaminant from drinking water. Biofiltration is simple and robust, and represents a green treatment technology. Studies have demonstrated potential of microbial degradation of fluorinated compounds, however the published information is very limited. The short-term impact of environmental occurrence PFOA concentration on biofilm bacterial community dynamics in a biofilter for drinking water treatment was examined. Fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) were applied as molecular methods for characterization of bacterial community dynamics. Bacterial community structure changed during continuous PFOA exposure, as demonstrated by both FISH and PCR-DGGE. FISH analysis of α-, β- and γ-proteobacteria revealed a significant shift from γ- to β-proteobacterial dominance in the biofilter communities in response to the polluted synthetic surface water