SCREENING AND CHARACTERIZATION OF TWO NEW DENITRIFYING PHOSPHORUS-REMOVAL BACTERIA

摘要

Two new strains of denitrifying phosphorus-removal bacteria (DPB) CL-1 and CL-3 were isolated from the sludge in the double sludge switching-sequencing batch reactor (DSSBR) which had been stably processed for two years. The strains were denitrifiers and contained meta-chromatic granules, which was found in polyphosphate-accumulating organisms (PAOs). From the phylogenetic analysis of their 16S rDNA gene sequences, CL-1 and CL-3 were identified as Pseudomonas oleovorans and Pseudomonas pseudoalcaligenes. The optimal temperature of their denitrifying and phosphorus removing was 30 °C; the optimal pH was 7-8. Nitrogen removal was analyzed in relation to the nitrate (NO_3"-N) concentration. The efficiency of nitrogen (N) removal and phosphorus (P) removal of CL-1 was 57% and 44% in the first 24 h, 76% and 57% in the 96 h, while CL-3 was 65% and 53% in the first 24 h, 85% and 77%. Compared with the other reported DPB, CL-3 showed higher N and P removal efficiency and was more applicable for wastewater with high NO_3"-N, indicating great potential of CL-3 for wastewater application. Isolation of DPB would be useful to determine the denitrifying P-removal process in detail and might be beneficial if it were to be inoculated into the wastewater in some future research.