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.

High-Throughput Amplicon Sequencing Reveals Distinct Communities within a Corroding Concrete Sewer System

“…It is possible that the lower variation in wall samples is the result of occasional inundation during flood events that may act to homogenize the wall environment and limit the development of niche communities. Bacterial populations, closely related to the abundant species detected here, have been reported, albeit at lower abundances (Ͻ3%), in other cultureindependent studies of sewer-associated MICC layers (11,16). Importantly, however, sequences derived from Acidithiobacillus spp.…”

“…appears to be exclusively associated with acidic, sulfur-oxidizing environments and currently has no cultured representatives. The most closely related Xanthomonadaceae sequences to this novel group are from the genus Rhodanobacter, which includes populations that are capable of sulfur oxidation (8), are abundant in an anaerobic acid environment (3), and have been previously reported in sewer corrosion environments (16). The wall-associated Sphingobacteriales spp.…”

“…Three recent studies have used clone libraries of the bacterial 16S rRNA gene to characterize the diversity and composition of microbial communities associated with MICC layers (11,16,17). These studies all indicate that while Acidithiobacillus spp.…”

“…can represent major components of some MICC layer communities, they are not ubiquitously dominant. These studies were limited, however, either being based on low sequencing depth (11,17) or focusing on samples taken from regions, such as manholes (16) or cement coupons in manholes (11), in which conditions are likely to be quite different from those in sewer pipe corrosion layers. Given that culture-dependent methods often poorly represent microbial diversity and that culture-independent methods have focused on samples that may differ from those from sewer pipes, knowledge of the microbial communities associated with MICC layers in sewer pipes needs to be improved.…”

Review of Microbially Induced Corrosion and Comments on Needs Related to Testing Procedures

“…(Islander et al, 1991). The presence of some or all of these microorganisms on corroded sewer pipes has been confirmed by multiple researchers through the use of genetic analysis (Davis, Nica, Shields, & Roberts, 1998;Okabe, Odagiri, Ito, & Satoh, 2007;Santo Domingo et al, 2011;Vincke, Boon, & Verstraete, 2001). …”