title: Submerged filter biofilm formation by nitrate-contaminated groundwater microbiota.
abstract: Denitrifying biofilms developed in a lab-scale submerged filter by autochthonous bacteria from nitrate-contaminated groundwater were studied. The system was supplied with groundwater (16 mg N-NO(3)(-)/L), from which the oxygen had been eliminated and to which an excess of carbon source had been added. The reactor was incubated in a thermostated chamber at 5°C, 10°C, 20°C and 30°C. Colonization of the support was studied using surface scanning microscopy, and biofilm bacterial composition was studied by PCR/TGGE. Support material was colonized at all the temperatures assayed, although this parameter affected the growth of the biofilm, which developed most at temperatures over 20°C. The composition of bacterial communities varied according to the temperature. Community profiles of the biofilm formed at 5°C and 10°C clustered away from those of the biofilm formed at 20°C and 30°C. 16S rDNA sequences reveled that the biofilm was mainly composed of psychrotolerant species typically inhabiting freshwaters, and we obtained sequencing bands that were affiliated to denitrifying and non-denitrifying heterotrophic species. The extent of colonization was low when compared to previously inoculated systems, and the capacity for nitrate elimination was also low.
authors.affiliation: Technologies for Water Management and Treatment Group, Department of Civil Engineering and Water Research Institute, University of Granada, Granada, Spain.
authors.forename: A
authors.initials: A
authors.lastname: de la Rua
authors.forename: B
authors.initials: B
authors.lastname: Rodelas
authors.forename: J
authors.initials: J
authors.lastname: González-López
authors.forename: M A
authors.initials: MA
authors.lastname: Gómez
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics; D018441:Biofilms; D005374:Filtration; D054892:Metagenome; D008854:Microscopy, Electron; D009566:Nitrates / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013696:Temperature; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D009566:Nitrates; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical