Simultaneous nitrogen removal via heterotrophic nitrification and aerobic denitrification by a novel Lysinibacillus fusiformis B301

Simultaneous nitrogen removal via heterotrophic nitrification and aerobic denitrification (HN-AD) has received widespread attention in biological treatment of wastewater. This study reported a novel Lysinibacillus fusiformis B301 strain, which effectively removed nitrogenous pollutants via HN-AD in one aerobic reactor with no nitrite accumulated. It exhibited the optimal nitrogen removal efficiency under 30 degrees C, citrate as the carbon source and C/N ratio of 15. The maximum nitrogen removal rates were up to 2.11 mgNH(4)(+)-N/(L center dot h), 1.62 mgNO(3)(-)-N/(L center dot h), and 1.41 mgNO(2)(-)-N/(L center dot h), respectively, when ammonium, nitrate, and nitrite were employed as the only nitrogen source under aerobic conditions. Ammonium nitrogen was preferentially consumed via HN-AD in the coexistence of three nitrogen species, and the removal efficiencies of total nitrogen were up to 94.26%. Nitrogen balance analysis suggested that 83.25% of ammonium was converted to gaseous nitrogen. The HD-AD pathway catalyzed by L. fusiformis B301 followed NH4+-> NH2OH -> NO2--> NO3--> NO2--> N2, supported by the results of key denitrifying enzymatic activities. Practitioner Points The novel Lysinibacillus fusiformis B301 exhibited the outstanding HN-AD ability.The novel Lysinibacillus fusiformis B301 simultaneously removed multiple nitrogen species.No nitrite accumulated during the HN-AD process.Five key denitrifying enzymes were involved in the HN-AD process.Ammonium nitrogen (83.25%) was converted to gaseous nitrogen by the novel strain.

Automated summary

This study presents a novel Lysinibacillus fusiformis B301 strain that effectively removes nitrogenous pollutants via heterotrophic nitrification and aerobic denitrification (HN-AD) in one aerobic reactor. Under optimal conditions, it achieved high nitrogen removal rates for ammonium, nitrate, and nitrite. The strain preferentially consumed ammonium nitrogen and converted 83.25% of it to gaseous nitrogen.