Few　indigenous　fungi　species　that　can　flocculate　microalgae　in　wastewater　treatment　plants　(WWTPs)　have　been　reported,　and　more　effective　fungi　strains　for　microalgal　flocculation　remain　to　be　identified.　In　this　research,　a　flocculating　fungi　strain　was　screened　from　a　WWTP.　The　flocculation　performance　and　properties　were　assessed.　The　underlying　mechanisms　were　elucidated　through　extracellular　polymeric　substances　(EPS)　analysis.　The　flocculation　conditions　were　optimized　by　the　response　surface　method　(RSM).　The　findings　indicated　that　the　isolated　strain　Curvularia　moringae　J-26　flocculated　Chlorella　sp.　with　an　efficiency　of　up　to　97.3　%　within　120　min.　Curvularia　moringae　J-26　flocculated　Chlorella　sp.　mainly　via　mycelium　absorption,　attributed　to　the　protein-like　(PN)　and　soluble　microbial　byproduct-like　substances　contained　in　the　EPS.　The　optimal　conditions　to　flocculate　Chlorella　sp.　were　the　mycelium　pellets　dosage　of　2.25　g/L　at　160　rpm　for　4.8　h.　Curvularia　moringae　J-26　flocculated　Chlorella　sp.　with　good　performance,　which　had　the　potential　to　reduce　the　cost　of　Chlorella　sp.　harvesting.　This　research　provided　a　technical　reference　for　Chlorella　sp.　harvesting　and　fungi　application　in　wastewater　treatment.　©　2025　Elsevier　Ltd