title: Genomic and in situ investigations of the novel uncultured Chloroflexi associated with 0092 morphotype filamentous bulking in activated sludge.
abstract: Overgrowth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) leads to impaired sludge settleability, a condition known as bulking, which is a common operational problem worldwide. Filaments with the Eikelboom 0092 morphotype are commonly associated with such bulking episodes. Members of the uncultured B45 phylotype, which is embraced within the phylum Chloroflexi, were recently shown to exhibit this morphology. Although these organisms are among the most abundant populations recorded in activated sludge processes, nothing is known about their metabolic characteristics. In this study, a genome sequence, representing the B45 phylotype, was retrieved from a metagenome generated from an activated sludge WWTP. The genome consisted of two chromosomes and one plasmid, which were 4.0, 1.0 and 0.04 Mbps in size, respectively. A metabolic model was constructed for this organism, based on annotation of its genome, showing its ability to generate energy by respiration, utilizing oxygen, nitrite or nitrous oxide as electron acceptors, or by fermentation of sugars. The ability of B45 members to ferment sugars under anaerobic conditions was validated in situ with microautoradiography-fluorescence in situ hybridization. The provisional name of 'Candidatus Promineofilum breve' is proposed for this species. This study represents the first detailed information on an uncultured genus of filamentous organisms from activated sludge.
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Simon Jon
authors.identifier: 0000-0003-3749-8730
authors.initials: SJ
authors.lastname: McIlroy
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Søren Michael
authors.initials: SM
authors.lastname: Karst
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Marta
authors.initials: M
authors.lastname: Nierychlo
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Morten Simonsen
authors.identifier: 0000-0003-4135-2670
authors.initials: MS
authors.lastname: Dueholm
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Albertsen
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Rasmus Hansen
authors.initials: RH
authors.lastname: Kirkegaard
authors.affiliation: Department of Microbiology, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Robert James
authors.initials: RJ
authors.lastname: Seviour
authors.affiliation: Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Per Halkjær
authors.initials: PH
authors.lastname: Nielsen
mesh_terms: D001483:Base Sequence; D041862:Chloroflexi / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005285:Fermentation; D016680:Genome, Bacterial / Q000235:genetics*; D023281:Genomics; D017404:In Situ Hybridization, Fluorescence; D053858:Metabolic Networks and Pathways / Q000235:genetics; D054892:Metagenome; D058977:Molecular Sequence Annotation; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*
chemical_list: D012722:Sewage