Key Physiology of Anaerobic Ammonium Oxidation

TLDR

The study quantitatively investigated the physiology of anammox aggregates grown in a sequencing batch reactor. Anammox aggregates operated optimally at pH 6.7–8.3 and 20–43 °C, had substrate affinities below 0.1 mg N L⁻¹, were fully inhibited by nitrite above 0.1 g N L⁻¹, and could be reactivated by trace hydrazine or hydroxylamine.

Abstract

ABSTRACT The physiology of anaerobic ammonium oxidizing (anammox) aggregates grown in a sequencing batch reactor was investigated quantitatively. The physiological pH and temperature ranges were 6.7 to 8.3 and 20 to 43°C, respectively. The affinity constants for the substrates ammonium and nitrite were each less than 0.1 mg of nitrogen per liter. The anammox process was completely inhibited by nitrite concentrations higher than 0.1 g of nitrogen per liter. Addition of trace amounts of either of the anammox intermediates (1.4 mg of nitrogen per liter of hydrazine or 0.7 mg of nitrogen per liter of hydroxylamine) restored activity completely.