In　endogenous　partial　denitrification　System　(EPD)　systems,　phosphorus　concentration　is　a　key　factor　regulating　the　community　structure　of　denitrifying　glycogen　accumulating　organisms　(DGAOs)　and　denitrifying　phosphorus　accumulating　organisms　(DPAOs).　Given　that　DPAOs　form　different　phosphorus　concentration　environments　through　phosphorus　release　during　the　anaerobic　phase,　it　is　important　to　explore　the　response　mechanism　of　DGAOs　under　different　phosphorus　concentration　disturbances　to　optimize　the　microbial　community　structure　in　EPD　systems.　In　this　study,　the　performance　of　EPD　system　driven　by　DGAOs,　sludge　physicochemical　characteristics　and　microbial　community　structure　differences　were　systematically　evaluated　by　simulating　different　phosphorus　concentration　conditions.　The　results　showed　that　the　appropriate　phosphorus　concentration　(6.00　and　15.00　mg/L)　environments　stimulated　the　secretion　of　extracellular　polymeric　substance　(EPS)　by　the　DGAOs　and　removed　phosphorus　mainly　by　adsorption/desorption　and　inorganic　precipitation/dissolution　of　PO43-　and　Ca²⁺　via　LB-EPS,　thus　maintaining　the　relative　stability　of　the　bacterial　community,　in　which　Defluviicoccus　(DGAOs)　relative　abundance　increased　from　0.71　%　to　4.17　%　(6　mg/L　PO43-)　and　4.79　%　(15　mg/L　PO43-),　respectively.　In　addition,　the　formation　of　inorganic　kernel　hydroxyapatite　(HAP)　promoted　sludge　granularity.　However,　the　high　phosphorus　concentration　(30　mg/L　PO43-)　environment　induced　algal　proliferation　in　the　EPD　system　leading　to　deterioration　of　performance.　This　study　revealed　the　potential　phosphorus　removal　capacity　of　the　EPD　system,　and　this　EPS-mediated　phosphorus　removal　not　only　reduced　the　carbon　source　consumption　of　the　system,　but　also　provided　new　perspectives　on　the　microbial　community　collaboration　between　DGAOs　and　DPAOs.　©　2025　Elsevier　Ltd