Highly efficient ammonium removal through nitrogen assimilation by a hydrogen-oxidizing bacterium, Ideonella sp. TH17

Ideonella sp. TH17, an autotrophic hydrogen-oxidizing bacterium (HOB), was successfully enriched and isolated from activated sludge in a domestic wastewater treatment plant (WWTP). Batch experiments were conducted to identify the cell growth and ammonium (NH4+-N) removal, and to verify the pathways of nitrogen utilization under different conditions. At a representative NH4+-N concentration of 100 mg/L in domestic wastewater, it was the first time that a HOB strain achieved a nearly 100% ammonium removal. More than 90% of NH4+-N was assimilated to biomass nitrogen by strain TH17. Only a little of N2 (