title: Characterisation of the physical composition and microbial community structure of biofilms within a model full-scale drinking water distribution system.
abstract: Within drinking water distribution systems (DWDS), microorganisms form multi-species biofilms on internal pipe surfaces. A matrix of extracellular polymeric substances (EPS) is produced by the attached community and provides structure and stability for the biofilm. If the EPS adhesive strength deteriorates or is overcome by external shear forces, biofilm is mobilised into the water potentially leading to degradation of water quality. However, little is known about the EPS within DWDS biofilms or how this is influenced by community composition or environmental parameters, because of the complications in obtaining biofilm samples and the difficulties in analysing EPS. Additionally, although biofilms may contain various microbial groups, research commonly focuses solely upon bacteria. This research applies an EPS analysis method based upon fluorescent confocal laser scanning microscopy (CLSM) in combination with digital image analysis (DIA), to concurrently characterize cells and EPS (carbohydrates and proteins) within drinking water biofilms from a full-scale DWDS experimental pipe loop facility with representative hydraulic conditions. Application of the EPS analysis method, alongside DNA fingerprinting of bacterial, archaeal and fungal communities, was demonstrated for biofilms sampled from different positions around the pipeline, after 28 days growth within the DWDS experimental facility. The volume of EPS was 4.9 times greater than that of the cells within biofilms, with carbohydrates present as the dominant component. Additionally, the greatest proportion of EPS was located above that of the cells. Fungi and archaea were established as important components of the biofilm community, although bacteria were more diverse. Moreover, biofilms from different positions were similar with respect to community structure and the quantity, composition and three-dimensional distribution of cells and EPS, indicating that active colonisation of the pipe wall is an important driver in material accumulation within the DWDS.
authors.affiliation: Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom; NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, Western Bank, Sheffield, United Kingdom.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Fish
authors.affiliation: Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Collins
authors.affiliation: Kroto Research Institute, The University of Sheffield, Sheffield, United Kingdom.
authors.forename: Nicola H
authors.initials: NH
authors.lastname: Green
authors.affiliation: Department of the Natural & Built Environment, Sheffield Hallam University, Sheffield, United Kingdom.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Sharpe
authors.affiliation: Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom.
authors.forename: Isabel
authors.initials: I
authors.lastname: Douterelo
authors.affiliation: School of Applied Sciences, RMIT University, PO Box 71 Bundoora, Melbourne, Australia.
authors.forename: A Mark
authors.initials: AM
authors.lastname: Osborn
authors.affiliation: Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom.
authors.forename: Joby B
authors.initials: JB
authors.lastname: Boxall
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D060766:Drinking Water / Q000382:microbiology*; D008962:Models, Theoretical; D014871:Water Microbiology; D060753:Water Quality; D014881:Water Supply
chemical_list: D060766:Drinking Water