title: Community structure of partial nitritation-anammox biofilms at decreasing substrate concentrations and low temperature.
abstract: Partial nitritation-anammox (PNA) permits energy effective nitrogen removal. Today PNA is used for treatment of concentrated and warm side streams at wastewater treatment plants, but not the more diluted and colder main stream. To implement PNA in the main stream, better knowledge about microbial communities at the typical environmental conditions is necessary. In order to investigate the response of PNA microbial communities to decreasing substrate availability, we have operated a moving bed biofilm reactor (MBBR) at decreasing reactor concentrations (311-27 mg-N l-1of ammonium) and low temperature (13°C) for 302 days and investigated the biofilm community using high throughput amplicon sequencing; quantitative PCR; and fluorescence in situ hybridization. The anammox bacteria (Ca. Brocadia) constituted a large fraction of the biomass with fewer aerobic ammonia oxidizing bacteria (AOB) and even less nitrite oxidizing bacteria (NOB; Nitrotoga, Nitrospira and Nitrobacter). Still, NOB had considerable impact on the process performance. The anammox bacteria, AOB and NOB all harboured more than one population, indicating some diversity, and the heterotrophic bacterial community was diverse (seven phyla). Despite the downshifts in substrate availability, changes in the relative abundance and composition of anammox bacteria, AOB and NOB were small and also the heterotrophic community showed little changes in composition. This indicates stability of PNA MBBR communities towards decreasing substrate availability and suggests that even heterotrophic bacteria are integral components of these communities.
authors.affiliation: Division of Water Environment Technology, Department of Civil and Environmental Engineering, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
authors.forename: Frank
authors.identifier: 0000-0002-0269-9375
authors.initials: F
authors.lastname: Persson
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, SE-40530, Gothenburg, Sweden.
authors.forename: Carolina
authors.initials: C
authors.lastname: Suarez
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, SE-40530, Gothenburg, Sweden.
authors.forename: Malte
authors.initials: M
authors.lastname: Hermansson
authors.affiliation: Department of Sustainable Development, Environmental Science and Engineering (SEED), Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44, Stockholm, Sweden.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Plaza
authors.affiliation: Department of Sustainable Development, Environmental Science and Engineering (SEED), Royal Institute of Technology (KTH), Teknikringen 76, SE-100 44, Stockholm, Sweden.
authors.forename: Razia
authors.initials: R
authors.lastname: Sultana
authors.affiliation: Division of Water Environment Technology, Department of Civil and Environmental Engineering, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
authors.forename: Britt-Marie
authors.initials: BM
authors.lastname: Wilén
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000254:growth & development* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology; D058448:Biota; D003080:Cold Temperature; D017404:In Situ Hybridization, Fluorescence; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013696:Temperature; D062065:Wastewater / Q000382:microbiology*
chemical_list: D000641:Ammonia; D009566:Nitrates; D062065:Wastewater