Molecular survey of concrete sewer biofilm microbial communities

Abstract

The microbial composition of concrete biofilms within wastewater collection systems was studied using molecular assays. SSU rDNA clone libraries were generated from 16 concrete surfaces of manholes, a combined sewer overflow, and sections of a corroded sewer pipe. Of the 2457 sequences analyzed, α-, β-, γ-, and δ-Proteobacteria represented 15%, 22%, 11%, and 4% of the clones, respectively. β-Proteobacteria (47%) sequences were more abundant in the pipe crown than any of the other concrete surfaces. While 178 to 493 Operational Taxonomic Units (OTUs) were associated with the different concrete samples, only four sequences were shared among the different clone libraries. Bacteria implicated in concrete corrosion were found in the clone libraries while archaea, fungi, and several bacterial groups were also detected using group-specific assays. The results showed that concrete sewer biofilms are more diverse than previously reported. A more comprehensive molecular database will be needed to better study the dynamics of concrete biofilms.

Keywords:

• concrete biofilm
• SSU rDNA sequences
• microbial diversity

Acknowledgements

This research was funded in part by EPA's Aging Water Infrastructure Research Program. The US Environmental Protection Agency, through its Office of Research and Development, funded and managed the research described herein. It has been subjected to the Agency's administrative review and has been approved for external publication. Any opinions expressed in this article are those of the author(s) and do not necessarily reflect the views of the Agency, therefore, no official endorsement should be inferred. Any mention of trade names or commercial products does not constitute endorsement or recommendation for use. Mr Biju George and Ms Beverly Head are acknowledged for valuable discussions and suggestions during the planning process, and for unlimited access to staff and facilities.