A kinetics study on anammox bacteria with a disproportionate substrate concentration

BACKGROUNDAnaerobic ammonia oxidation, or anammox, is one of the most efficient techniques to dispose of sewage ammonia nitrogen and nitrite nitrogen within a reactor. Kinetics equations of anammox have been studied under proportions of ammonia nitrogen and nitrite nitrogen in the laboratory, however, in wastewater treatment, the reaction conditions are variable and unstable.RESULTSTwo strains of anammox bacteria, Candidatus Brocadia fulgida and Candidatus Brocadia caroliniensis, were identified by PCR and assigned the formal bacterial serial numbers: KR005667 and KR005668, respectively. The degradation curves of the two anammox bacteria were drawn by calculating the kinetics parameters using the Michaelis-Menten equation, and the ammonia oxidation rates, nitrite conversion rates and Km values of ammonia and nitrite were close to or identical to the known data range of the kinetics of anammox bacteria metabolism.CONCLUSIONA hypothesis regarding the role of extracellular polymeric substance (EPS) was proposed and the reaction mechanism of anammox bacteria was deduced in the case of a disproportionate substrate concentration.