Polyhydroxyalkanoates　(PHA)　recovery　from　industrial　wastewater　has　been　highlighted　as　a　promising　strategy　for　a　circular　bioeconomy.　However,　the　high　and　varying　level　of　nitrogen　in　wastewater　makes　enrichment　of　mixed　microbial　culture　(MMC)　low　efficiency.　In　this　study,　spatial　separation　of　nitrifiers　and　denitrifiers　was　adopted　by　adding　biocarriers　in　MMC　and　decreasing　the　sludge　retention　time　(SRT)　to　accelerate　the　enrichment　of　PHA-storing　MMC　fed　by　mixed　wastewater　containing　glycerol　and　propionate.　Nitrifiers　and　denitrifiers　were　sustained　on　biocarriers,　obtaining　a　high　total　inorganic　nitrogen　removal　and　allowing　a　more　efficient　selective　pressure　of　a　high　carbon　and　nitrogen　ratio　(C/N)　under　low　SRT　conditions.　The　maximum　PHA　cell　content　and　relative　abundance　of　PHA-storing　bacteria　were　increased　to　60.51　%　(SRT　6　d)　and　49.62　%　(SRT　6　d)　with　the　decrease　of　SRT,　respectively.　This　study　demonstrates　an　efficient　way　to　highly　enrich　PHA-storing　MMC　from　crude　glycerol,　which　provide　a　relevant　technical　support　for　high-efficiency　enrichment　of　PHA-storing　bacteria　in　low　C/N　wastewater.　©　2024　Elsevier　B.V.