Community profiling of bacteria in sewer biofilms
Résumé
Despite the fact that microorganisms are important for both the function of sewers and potential ecological or public health risk due to sewer failures, little is currently known about the diversity of microbial communities present within the sewers. Sewer biofilms are in this context of particular interest as the microbial load in biofilms is significantly higher than in the flowing wastewater. In this study the microbial community of biofilms sampled from three different sites, in two different sewer systems, in dry weather, was characterized. This was performed using denaturant gradient gel electrophoresis (DGGE) for community profiling and fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH) for visualisation. DGGE profiling showed good reproducibility within the triplicate samples from two of the three sampling sites. A total of 26 bands were detected on the electrophoresis gel. Of these, 4 were found in all three sites and 10 were unique to one site only. This illustrates considerable microbial diversity within sewer biofilms even at sites which are predominantly combined sewer catchments.