Nitrogen removal and mechanism of an extremely high-ammonia tolerant heterotrophic nitrification-aerobic denitrification bacterium Alcaligenes faecalis TF-1.

A novel heterotrophic nitrifying bacterium with high salt and high ammonia nitrogen tolerance, Alcaligenes faecalis TF-1, was isolated from the leachate of a landfill. The verification of nitrogen removal efficiency of different nitrogen sources and PCR amplification electrophoresis results showed that the HN-AD pathway of the strain TF-1 was NH → NHOH → NO → NO → N. The results of parameter optimization showed that the optimal nitrogen removal conditions were as follows: sodium citrate as carbon source, C/N = 16, pH = 7, and NH-N loading of 808.21 mg/L. The strain TF-1 could remove about 94.60% of ammonia nitrogen (1963.94 mg/L). The salinity tolerance range of the strain TF-1 was 0-70 g/L, and the removal efficiency was 52.87% at salinity 70 g/L and NH-N concentration 919.20 mg/L and 55.67% at pH = 10 and NH-N concentration 994.82 mg/L. The extreme environmental adaptability and remarkable nitrogen removal performance make this strain a promising candidate in leachate treatment.