Isolation, Identification and Nitrogen Removal Characteristics of Aerobic Denitrifying Bacillus Strain JD-014

Abstract:

A strain of Bacillus subtilis JD-014 with aerobic denitrification function was isolated and screened out from a river course in this study to treat and remove the nitrogen pollutants in food industrial wastewater in a green and environmentally friendly way. The aerobic denitrification pathway within this strain was verified by the gaseous nitrogen production, the nitrogen balance calculation and the functional enzymatic activity measurement during the nitrogen removal process. The effect of different environmental factors on its nitrogen removal performance was investigated as well. The results showed that the nitrogen removal rate of JD-014 was 0.56 mg/（L·h） when sodium nitrate (50 mg/L) was used as the sole nitrogen source. The strain was found to partly transfer the NO₃^--N into N₂ accompanied by the detection of related functional enzyme activity. The optimal conditions for JD-014 to achieve the best nitrogen removal performance were carbon source of sodium succinate or sodium citrate, C/N ratio of 10 to 25, temperature of 37 ℃, shaking speed of 150 to 200 r/min, and salinity of less than 1%. Moreover, JD-014 had great nitrite tolerance, and the nitrogen removal efficacy could be kept within 46.62%~99.92% when the concentration of NO₂^--N was 10~200 mg/L. These results suggested that the aerobic denitrifying B. subtilis JD-014 had great potential in the biological treatment of nitrogen pollution in food processing wastewater.