Glycogen　accumulating　organisms　(GAOs)　capable　of　storing　organic　compounds　as　polyhydroxyalkanoate　(PHA)　have　been　used　for　endogenous　denitritation　(ED),　but　the　effect　of　carbon　sources　type　on　nitrogen　removal　performance　of　GAOs　treating　landfill　leachate　is　unclear.　In　this　study,　a　successful　ED　system　treating　landfill　leachate　(COD/NH4+-N　(C/N):　4)　without　external　carbon　source　addition　was　applied.　The　mature　leachate　with　C/N　of　1　was　used　as　the　feeding　base　solution,　with　acetate,　propionate,　and　glucose　examined　as　the　carbon　sources,　and　their　effects　on　yields　and　compositions　of　PHA　produced　by　GAOs　were　determined　and　associated　with　nitrogen　removal　performance.　In　the　case　of　sole　carbon　source,　acetate　was　much　easier　to　be　stored　than　propionate　and　glucose,　which　led　to　a　higher　nitrogen　removal　efficiency.　Glucose　had　the　lowest　amount　of　PHA　storage　and　led　to　the　lowest　performance.　In　the　case　of　composite　carbon　sources　(two　scenarios:　acetate　+　propionate;　acetate　+　propionate　+　glucose),　GAOs　stored　sufficient　PHA　and　exhibited　similar　nitrogen　removal　efficiencies.　Moreover,　type　of　carbon　source　influenced　the　compositions　of　PHA.　The　polyhydroxybutyrate　(PHB)　fraction　in　PHA　was　far　more　than　polyhydroxyvalerate　(PHV)　in　all　tests.　PHV　was　synthesized　only　when　acetate　existed　in　carbon　source.　The　microbial　diversity　analysis　revealed　that　Proteobacteria　was　the　most　abundant　phylum.　Among　the　108　genera　detected　in　this　ED　system,　the　genera　responsible　for　denitritation　were　Thauera,　Paracoccus,　Ottowia　and　Comamonadaceae_unclassified,　accounting　for　46.21%　of　total　bacteria.　Especially,　Paracoccus　and　Comamonadaceae_unclassified　transformed　the　carbon　source　into　PHA　for　denitritation,　and　carried　out　endogenous　denitritation.　(c)　2016　Elsevier　Ltd.