Nitrate Reverses Severe Nitrite Inhibition of Anaerobic Ammonium Oxidation (Anammox) Activity in Continuously-Fed Bioreactors
Krzmarzick, Mark J
Field, Jim A.
AffiliationUniversity of Arizona
MetadataShow full item record
PublisherAMER CHEMICAL SOC
CitationNitrate Reverses Severe Nitrite Inhibition of Anaerobic Ammonium Oxidation (Anammox) Activity in Continuously-Fed Bioreactors 2016, 50 (19):10518 Environmental Science & Technology
Rights© 2016 American Chemical Society
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AbstractNitrite (NO2-) substrate under certain conditions can cause failure of N-removal processes relying on anaerobic ammonium oxidizing (anammox) bacteria. Detoxification of NO2- can potentially be achieved by using exogenous nitrate (NO3-). In this work, continuous experiments in bioreactors with anammox bacteria closely related to “Candidatus Brocadia caroliniensis” were conducted to evaluate the effectiveness of short NO3- additions to reverse NO2- toxicity. The results show that a timely NO3- addition immediately after a NO2- stress event completely reversed the NO2- inhibition. This reversal occurs without NO3- being metabolized as evidence by lack of any 30N2 formation from 15N-NO3-. The maximum recovery rate was observed with 5 mM NO3- added for 3 days; however, slower but significant recovery was also observed with 5 mM NO3- for 1 day or 2 mM NO3- for 3 days. Without NO3- addition, long-term NO2- inhibition of anammox biomass resulted in irreversible damage of the cells. These results suggest that a short duration dose of NO3- to an anammox bioreactor can rapidly restore the activity of NO2--stressed anammox cells. On the basis of the results, a hypothesis about the detoxification mechanism related to narK genes in anammox bacteria is proposed and discussed.
NotePublication Date (Web): September 6, 2016. 12 month embargo.
VersionFinal accepted manuscript
SponsorsThis work was supported by the University of Arizona Water Sustainability Program, and the National Science Foundation (Contract CBET-1234211)