N2O production rate of an enriched ammonia-oxidising bacteria culture exponentially correlates to its ammonia oxidation rate

Water Res. 2012 Jun 15;46(10):3409-19. doi: 10.1016/j.watres.2012.03.043. Epub 2012 Apr 3.


The relationship between the ammonia oxidation rate (AOR) and nitrous oxide production rate (N(2)OR) of an enriched ammonia-oxidising bacteria (AOB) culture was investigated. The AOB culture was enriched in a nitritation system fed with synthetic anaerobic digester liquor. The AOR was controlled by adjusting the dissolved oxygen (DO) and pH levels and also by varying the initial ammonium (NH(4)(+)) concentration in batch experiments. Tests were also performed directly on the parent reactor where a stepwise decrease/increase in DO was implemented to alter AOR. The experimental data indicated a clear exponential relationship between the biomass specific N(2)OR and AOR. Four metabolic models were used to analyse the experimental data. The metabolic model formulated based on aerobic N(2)O production from the decomposition of nitrosyl radical (NOH) predicted the exponential correlation observed experimentally. The experimental data could not be reproduced by models developed on the basis of N(2)O production through nitrite (NO(2)(-)) and nitric oxide (NO) reduction by AOB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonia / metabolism*
  • Bacteria / growth & development*
  • Bacteria / metabolism*
  • Batch Cell Culture Techniques / methods*
  • Biodegradation, Environmental
  • Hydrogen-Ion Concentration
  • Models, Biological
  • Nitrous Oxide / metabolism*
  • Oxidation-Reduction
  • Oxygen / analysis
  • Reproducibility of Results


  • Ammonia
  • Nitrous Oxide
  • Oxygen