Nitrogen removal characteristics of a novel heterotrophic nitrification and aerobic denitrification bacteria, Alcaligenes faecalis strain WT14.

Alcaligenes faecalis strain WT14 is heterotrophic nitrification and aerobic denitrification bacterium, newly isolated from a constructed wetland, and its feasibility in nitrogen removal was investigated. The result showed sodium citrate was more readily utilized by WT14 as a carbon source. The response surface methodology model revealed the highest total nitrogen removal by WT14 occurred at 20.3 °C, 113.5 r·min-1, C/N 10.8, and pH 8.4. Under adapted environmental conditions, up to 55.9 mg·L-1·h-1 of ammonium nitrogen (NH4+-N) was removed by WT14, and its NH4+-N tolerance ability reached 2000 mg·L-1. In addition to the reported high NH4+-resistance of Alcaligenes faecalis, WT14 multiplied fast and had strong nitrate or nitrite removal capacity when high strength nitrate or nitrite was provided as the single nitrogen source; which differed from other Alcaligenes faecalis species. These results show WT14 is a novel strain of Alcaligenes faecalis and its nitrogen removal pathway will be carried out in the further study.