[Selection of denitrifying phosphorus-removing bacteria and its characteristic]

Using YG culture medium, combined with the experiments of blue-and white-colored screening, Albert staining and detection of phosphorus removal capacity, seven phosphorus-removing bacterium were isolated from activated sludge collected from aerobic biochemical pool of wastewater treating factory. After nitrate reducing and anoxic culturing experiment, a strain with high capability of denitrifying and phosphorus removing was selected. With the study of its physiology and biochemistry and the analysis of its 16S rRNA gene, this strain was identified as Pseudomonas grimontii, and named of C18. The phosphorus removal rate of C18 was 94.1% under aerobic condition in 24 hours (The phosphorus concentration in supernatant was 38.7 mg/L to 2.28 mg/L). The phosphorus removal rate of C18 was 88.3% under anoxic condition in 24 hours (the phosphorus concentration in supernatant was 44.5 mg/L to 5.21 mg/L), and the denitrifying rate of C18 was 83.4% under anoxic condition in 24 hours (the nitrate concentration in supernatant was 184.2 mg/L to 30.6 mg/L). The optimal temperature of C18 denitrifying and phosphorus removing was 30 degrees C; The optimal pH of C18 denitrifying and phosphorus removing was 7.5.