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CHANGES IN BACTERIAL COMPOSITION OF BIOFILM IN A METROPOLITAN DRINKING WATER DISTRIBUTION SYSTEM
Revetta, R., V. Gomez-Alvarez, T. Gerke, J. Santodomingo, AND N. Ashbolt. CHANGES IN BACTERIAL COMPOSITION OF BIOFILM IN A METROPOLITAN DRINKING WATER DISTRIBUTION SYSTEM. JOURNAL OF APPLIED MICROBIOLOGY. John Wiley & Sons Inc, Malden, MA, 121(1):294-305, (2016).
The purpose of this research was to add to our knowledge of the differences in drinking water distribution system biofilms, with regards to effects of source water, treatment processes, and environmental conditions. A 16S rRNA sequencing-based approach was used to assess the microbial community and the metabolic potential in these communities.
This study examined the development of bacterial biofilms within a metropolitan distribution system. The distribution system is fed with different source water (i.e., groundwater, GW and surface water, SW) and undergoes different treatment processes in separate facilities. The biofilm community was characterized using 16S rRNA gene clone libraries and functional potential analysis, generated from total DNA extracted from coupons in biofilm annular reactors fed with onsite drinking water for up to eighteen months. Significant differences in the bacterial community structure were observed between GW and SW. Representatives that explained the dissimilarity between service areas were associated with Betaproteobacteria, Alphaproteobacteria, Actinobacteria, Gammaproteobacteria, and Firmicutes. After nine months the biofilm bacterial community from both areas were dominated by Mycobacterium species. The distribution of the dominant OTU (Mycobacterium) positively correlated with the drinking water distribution system (DWDS) temperature, but no clear relationship was seen with free chlorine residual, pH, turbidity or total organic carbon (TOC). The results suggest that biofilm microbial communities harbor distinct and diverse bacterial communities, and that source water, treatment processes and environmental conditions may play an important role in shaping the bacterial community in the distribution system. On the other hand, several bacterial groups were present in all samples, suggesting that they are an integral part of the core microbiota of this DWDS. These results provide an ecological insight into biofilm bacterial structure in chlorine-treated drinking water and the effect of source water and/or water quality parameters in their development.