Dataset Information

Identification of bacteria in biofilm and bulk water samples from a nonchlorinated model drinking water distribution system: detection of a large nitrite-oxidizing population associated with Nitrospira spp.

ABSTRACT: In a model drinking water distribution system characterized by a low assimilable organic carbon content (<10 microg/liter) and no disinfection, the bacterial community was identified by a phylogenetic analysis of rRNA genes amplified from directly extracted DNA and colonies formed on R2A plates. Biofilms of defined periods of age (14 days to 3 years) and bulk water samples were investigated. Culturable bacteria were associated with Proteobacteria and Bacteriodetes, whereas independently of cultivation, bacteria from 12 phyla were detected in this system. These included Acidobacteria, Nitrospirae, Planctomycetes, and Verrucomicrobia, some of which have never been identified in drinking water previously. A cluster analysis of the population profiles from the individual samples divided biofilms and bulk water samples into separate clusters (P = 0.027). Bacteria associated with Nitrospira moscoviensis were found in all samples and encompassed 39% of the sequenced clones in the bulk water and 25% of the biofilm community. The close association with Nitrospira suggested that a large part of the population had an autotrophic metabolism using nitrite as an electron donor. To test this hypothesis, nitrite was added to biofilm and bulk water samples, and the utilization was monitored during 15 days. A first-order decrease in nitrite concentration was observed for all samples with a rate corresponding to 0.5 x 10(5) to 2 x 10(5) nitrifying cells/ml in the bulk water and 3 x 10(5) cells/cm(2) on the pipe surface. The finding of an abundant nitrite-oxidizing microbial population suggests that nitrite is an important substrate in this system, potentially as a result of the low assimilable organic carbon concentration. This finding implies that microbial communities in water distribution systems may control against elevated nitrite concentrations but also contain large indigenous populations that are capable of assisting the depletion of disinfection agents like chloramines.

SUBMITTER: Martiny AC

PROVIDER: S-EPMC1317318 | biostudies-literature | 2005 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identification of bacteria in biofilm and bulk water samples from a nonchlorinated model drinking water distribution system: detection of a large nitrite-oxidizing population associated with Nitrospira spp.

Martiny Adam C AC Albrechtsen Hans-Jørgen HJ Arvin Erik E Molin Søren S

Applied and environmental microbiology 20051201 12

In a model drinking water distribution system characterized by a low assimilable organic carbon content (<10 microg/liter) and no disinfection, the bacterial community was identified by a phylogenetic analysis of rRNA genes amplified from directly extracted DNA and colonies formed on R2A plates. Biofilms of defined periods of age (14 days to 3 years) and bulk water samples were investigated. Culturable bacteria were associated with Proteobacteria and Bacteriodetes, whereas independently of culti ...[more]

PMID: 16332854

Similar Datasets

Project description:Nitrite-oxidizing bacteria are vital players in the global nitrogen cycle that convert nitrite to nitrate during the 2nd step of nitrification. Within this functional guild, the genus Nitrospira is among the most widespread and phylogenetically and physiologically diverse nitrite oxidizers and its members drive nitrite oxidation in many natural and biotechnological ecosystems. Despite their ecological and biotechnological importance, our understanding of Nitrospira’s energy metabolism is still limited. The main bottleneck for a detailed biochemical characterization of Nitrospira is biomass production, since they are slow-growing organisms and fastidious to culture. In this study, we cultured Nitrospira moscoviensis in a continuous stirred tank reactor system (CSTR) allowing constant biomass harvesting. Additionally, this cultivation setup enabled accurate control of physicochemical parameters and thus avoided fluctuating levels of nitrite and accumulation of nitrate. We performed transcriptome analysis and confirmed constant gene expression profiles in the chemostat culture over a period of two weeks. The transcriptomic data supports the predicted core metabolism of N. moscoviensis, including the reductive TCA cycle as a CO2 fixation pathway, the novel bd-like oxidase as terminal oxidase and the octaheme nitrite reductase involved in nitrogen assimilation. Additionally, the expression of multiple copies of respiratory complexes suggests functional differentiation of these copies within the respiratory chain. Transcriptome analysis also suggests a soluble and a membrane-bound gamma subunit as part of the nitrite oxidoreductase (NXR), the enzyme catalyzing nitrite oxidation. Overall, the transcriptome data provided novel insights into the metabolism of Nitrospira supporting the genome-based prediction of key pathways. Moreover, the application of a CSTR to cultivate Nitrospira is an important foundation for future proteomic and biochemical characterizations, which are crucial for a better understanding of canonical and complete nitrifying microorganisms.

Dataset Information

Identification of bacteria in biofilm and bulk water samples from a nonchlorinated model drinking water distribution system: detection of a large nitrite-oxidizing population associated with Nitrospira spp.

Publications

Identification of bacteria in biofilm and bulk water samples from a nonchlorinated model drinking water distribution system: detection of a large nitrite-oxidizing population associated with Nitrospira spp.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure