Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Influent:Real wastewater
Comammox System:MBfR coupling anammox and n-DAMO
reactor:MBfR (biofilm)
Medium:Biofilm-suspended-growth
Culture taken from:Enriched n-DAMO archaea and anammox bacteria culture
Microorganism cultured:n-DAMO archaea and n-DAMO bacteria
Respiration:Anaerobic
Electron donor:Methane
Electron acceptor:Nitrite
PH:7.0–7.5
Temperature:22°C
HRT:nan
NH4–N Influent conc(mg/L):nan
NO2–N Influent conc(mg/L):nan
NO3–N Influent conc(mg/L):nan
NH4–N Effluent (mg N/L):nan
NO2–N Effluent (mg N/L):nan
NO3-N Effluent (mg N/L):nan
NH4–N removal rate mg/L/d:60
NO2–N removal rate mg/L/d:nan
NO3-N removal rate mg/L/d:190
TN Removal rate (mg N/L/d):nan
Authors:van Kessel et al., 2015
Title:Complete nitrification by a single microorganism
Pubmed link:None
Full research link:Link
Abstract:Nitrification is a two-step process where ammonia is first oxidized to nitrite by ammonia-oxidizing bacteria and/or archaea, and subsequently to nitrate by nitrite-oxidizing bacteria. Already described by Winogradsky in 18901, this division of labour between the two functional groups is a generally accepted characteristic of the biogeochemical nitrogen cycle2. Complete oxidation of ammonia to nitrate in one organism (complete ammonia oxidation; comammox) is energetically feasible, and it was postulated that this process could occur under conditions selecting for species with lower growth rates but higher growth yields than canonical ammonia-oxidizing microorganisms3. Still, organisms catalysing this process have not yet been discovered. Here we report the enrichment and initial characterization of two Nitrospira species that encode all the enzymes necessary for ammonia oxidation via nitrite to nitrate in their genomes, and indeed completely oxidize ammonium to nitrate to conserve energy. Their ammonia monooxygenase (AMO) enzymes are phylogenetically distinct from currently identified AMOs, rendering recent acquisition by horizontal gene transfer from known ammonia-oxidizing microorganisms unlikely. We also found highly similar amoA sequences (encoding the AMO subunit A) in public sequence databases, which were apparently misclassified as methane monooxygenases. This recognition of a novel amoA sequence group will lead to an improved understanding of the environmental abundance and distribution of ammonia-oxidizing microorganisms. Furthermore, the discovery of the long-sought-after comammox process will change our perception of the nitrogen cycle.