Nitrate Reverses Severe Nitrite Inhibition of Anaerobic Ammonium Oxidation (Anammox) Activity in Continuously-Fed Bioreactors.
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 any30N2formation from15N-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.
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
Guangbin
G
Li
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
Reyes
R
Sierra-Alvarez
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
David
D
Vilcherrez
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
Stefan
S
Weiss
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
Callie
C
Gill
School of Civil and Environmental Engineering, Oklahoma State University , 207 Engineering, South Stillwater, Oklahoma 74078, United States.
Mark J
MJ
Krzmarzick
Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721-0041, United States.|Department of Soil, Water & Environmental Science, University of Arizona , Tucson, Arizona 85721-0041, United States.
Leif
L
Abrell
Department of Chemical and Environmental Engineering, University of Arizona , 1133 E. James E. Rogers Way, Tucson, Arizona 85721-001, United States.
Jim A
JA
Field
D064751:Ammonium Compounds / Q000378:metabolism; D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
D064751:Ammonium Compounds; D009566:Nitrates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D009584:Nitrogen