title: Distribution of Nitrosomonas europaea and Nitrobacter winogradskyi in an autotrophic nitrifying biofilm reactor as depicted by molecular analyses and mathematical modelling.
abstract: The autotrophic two-species biofilm from the packed bed reactor of a life-support system, containing Nitrosomonas europaea ATCC 19718 and Nitrobacter winogradskyi ATCC 25391, was analysed after 4.8 years of continuous operation performing complete nitrification. Real-time quantitative polymerase chain reaction (Q-PCR) was used to quantify N. europaea and N. winogradskyi along the vertical axis of the reactor, revealing a spatial segregation of N. europaea and N. winogradskyi. The main parameters influencing the spatial segregation of both nitrifiers along the bed were assessed through a multi-species one-dimensional biofilm model generated with AQUASIM software. The factor that contributed the most to this distribution profile was a small deviation from the flow pattern of a perfectly mixed tank towards plug-flow. The results indicate that the model can estimate the impact of specific biofilm parameters and predict the nitrification efficiency and population dynamics of a multispecies biofilm.
authors.affiliation: Department of Chemical Engineering, Universitat Autònoma de Barcelona, ETSE, Ed. Q, 08193 Barcelona, Spain. anna.montras@uab.cat
authors.forename: Anna
authors.initials: A
authors.lastname: Montràs
authors.forename: Benny
authors.initials: B
authors.lastname: Pycke
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Francesc
authors.initials: F
authors.lastname: Gòdia
authors.forename: Max
authors.initials: M
authors.lastname: Mergeay
authors.forename: Larissa
authors.initials: L
authors.lastname: Hendrickx
authors.forename: Julio
authors.initials: J
authors.lastname: Pérez
mesh_terms: D001483:Base Sequence; D018441:Biofilms; D019149:Bioreactors; D017931:DNA Primers; D017404:In Situ Hybridization, Fluorescence; D008962:Models, Theoretical; D009576:Nitrobacter / Q000235:genetics / Q000302:isolation & purification*; D009606:Nitrosomonas / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S