Search

A novel heterotrophic nitrification and aerobic denitrification (HNAD) bacteria, identified as Bacillus thuringiensis strain WXN-23, was isolated from husk feed filtrate of a pig farm. It was the first report of Bacillus thuringiensis with the capability for HNAD and could adapt to the condition of low Carbon/Nitrogen (C/N) ratio. Nitrogen could be efficiently removed by the strain WXN-23 in simulated wastewater, be it in single or mixed form nitrogen sources. The nitrogen balance revealed that 63.5% of the initial nitrogen (5.32 mg) was lost in the form of N 2. The conditions for maximum total nitrogen (TN) removal efficiency (95.996%) were shaking speed of 126.89 r/min, a carbon C/N ratio of 5.91, the temperature of 32.81 °C, and a pH value of 8.17. The nitrification-denitrification metabolic pathway (NH 4 +–N→NH 2 OH→NO 2 −-N→NO 3 −-N→NO 2 −-N→NO→N 2 O→N 2) under aerobic conditions was determined on the basic of characteristic of N removal, N balance analysis, enzyme assay and functional genes amplification results. Strain WXN-23 was effective at wastewater treatment, with TN, NH 4 +-N, NO 3 −-N and NO 2 −-N removal efficiencies of 82.12%, 86.74%, 90.74% and 100%, respectively. • Found a heterotrophic nitrifying and aerobic denitrification Bacillus thuringiensis strain. • Bacillus thuringiensis strain WXN-23 can adapt to the condition of low C/N ratio. • Strain WXN-23 can efficiently remove nitrogen from water under aerobic conditions. • Hardly any greenhouse gas was generated by strain WXN-23 during nitrogen removal. [ABSTRACT FROM AUTHOR]