title: The role of inoculum and reactor configuration for microbial community composition and dynamics in mainstream partial nitritation anammox reactors.
abstract: Implementation of partial nitritation anammox (PNA) in the mainstream (municipal wastewater treatment) is still under investigation. Microbial community structure and reactor type can influence the performance of PNA reactor; yet, little is known about the role of the community composition of the inoculum and the reactor configuration under mainstream conditions. Therefore, this study investigated the community structure of inocula of different origin and their consecutive community dynamics in four different lab-scale PNA reactors with 16S rRNA gene amplicon sequencing. These reactors were operated for almost 1 year and subjected to realistic seasonal temperature fluctuations as in moderate climate regions, that is, from 20°C in summer to 10°C in winter. The sequencing analysis revealed that the bacterial community in the reactors comprised: (1) a nitrifying community (consisting of anaerobic ammonium-oxidizing bacteria (AnAOB), ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB)); (2) different heterotrophic denitrifying bacteria and other putative heterotrophic bacteria (HB). The nitrifying community was the same in all four reactors at the genus level, although the biomasses were of different origin. Community dynamics revealed a stable community in the moving bed biofilm reactors (MBBR) in contrast to the sequencing batch reactors (SBR) at the genus level. Moreover, the reactor design seemed to influence the community dynamics, and reactor operation significantly influenced the overall community composition. The MBBR seems to be the reactor type of choice for mainstream wastewater treatment.
authors.affiliation: Technische Universität Darmstadt, Institute IWAR, Chair of Wastewater Engineering, Darmstadt, Germany.|Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair for Water Chemistry and Water Technology, Karlsruhe, Germany.
authors.forename: Shelesh
authors.identifier: 0000-0001-9365-5951
authors.initials: S
authors.lastname: Agrawal
authors.affiliation: Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark.
authors.forename: Søren M
authors.initials: SM
authors.lastname: Karst
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair for Water Chemistry and Water Technology, Karlsruhe, Germany.|EnviroChemie GmbH, Rossdorf, Germany.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Gilbert
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair for Water Chemistry and Water Technology, Karlsruhe, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Horn
authors.affiliation: Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark.
authors.forename: Per H
authors.initials: PH
authors.lastname: Nielsen
authors.affiliation: Technische Universität Darmstadt, Institute IWAR, Chair of Wastewater Engineering, Darmstadt, Germany.|Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair for Water Chemistry and Water Technology, Karlsruhe, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Lackner
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D058448:Biota; D016000:Cluster Analysis; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D058440:Denitrification; D058465:Nitrification; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D064751:Ammonium Compounds; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: Molecular microbial ecology; Nitrogen metabolism; biofilm; bioreactors