[Effects of Long-term Poly-P Deficiency on the Metabolic Properties of Accumulibacter in AO-SBR System].

To investigate the changes in microbial community structure and metabolic properties of Accumulibacter under long-term Poly-P deficiency, an activated sludge enriched with Accumulibacter was inoculated into two SBR reactors, where sodium acetate and sodium propionate were used separately as organic carbon sources. The two reactors were operated for 60 days with an influent PO43--P concentration of 2.5 mg·L-1. The phosphorus removal performance, sludge production, and changes in the microbial community structure of the systems were analyzed. The results indicated that both SBR systems showed good performance of phosphorus and organic matter removal. However, microorganisms in both systems showed glycogen-accumulating metabolism properties under long-term Poly-P deficiency. In the unfavorable environment of long-term Poly-P deficiency, Accumulibacter Ⅰ maintained a high abundance (40%±7%) in the propionate SBR system, indicating that Accumulibacter Ⅰ had higher metabolic activity and its metabolic properties could be independent of Poly-P for survival under Poly-P deficiency for a long period. In comparison, propionate is more conducive to Accumulibacter adaptation to lower phosphorus loads, and Accumulibacter Ⅰ is more competitive than Accumulibacter Ⅱ under lower phosphorus loads.