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Establishment and Early Succession of Bacterial Communities in Monochloramine-treated Drinking Water Biofilms
Citation:
Revetta, R., V. Gomez-Alvarez, T. Gerke, C. Curioso, J. Santodomingo, AND N. Ashbolt. Establishment and Early Succession of Bacterial Communities in Monochloramine-treated Drinking Water Biofilms. Presented at American Society for Microbiology, Denver, CO, May 18 - 21, 2013.
Impact/Purpose:
To inform scientific community of project/results.
Description:
The use of monochloramine as drinking water disinfectant is increasing because it forms lower levels of traditional disinfection by-products compared to free-chlorine. However, little is known about the bacterial succession within biofilms in monochloramine-treated systems. The development and succession of bacteria were examined by 16S rRNA gene clone libraries generated from various biofilms within a water distribution system simulator. Biofilms were obtained from in-line and off-line devices using borosilicate glass beads, along with polycarbonate coupons from annular reactors incubated for up to eight months in monochloramine-treated drinking water. Overall, 90% of the diversity in all the clone library samples was associated with the phyla Proteobacteria, Actinobacteria and Bacteroidetes. No significant difference in community structures, as measured using non-metric multidimensional scaling, were observed between biofilm devices or coupon material. However, all biofilm communities that developed on different devices underwent similar successions over time. Early stages of biofilm formation (up to 2 months) were dominated by Serratia (29%), Cloacibacterium (23%), Diaphorobacter (16%), and Pseudomonas (7%), while Mycobacterium-like phylotypes were the most predominant populations (>27%) in subsequent months (≥3 months). The occurrence of members of the non-tuberculous mycobacteria (NTM) in drinking water distribution systems may affect individuals with predisposing conditions, while the establishment of nitrifiers (related to Nitrospira moscoviensis and Nitrosospira multiformis) in the late stages of biofilm development, could impact water quality. These results provide an ecological insight into biofilm bacterial successions in monochloramine-treated drinking water biofilms.