Nitrite (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.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621475 |
| Date | 04 October 2016 |
| Creators | Li, Guangbin, Sierra-Alvarez, Reyes, Vilcherrez, David, Weiss, Stefan, Gill, Callie, Krzmarzick, Mark J, Abrell, Leif, Field, Jim A. |
| Contributors | University of Arizona |
| Publisher | AMER CHEMICAL SOC |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016 American Chemical Society |
| Relation | http://pubs.acs.org/doi/abs/10.1021/acs.est.6b01560 |
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