In　order　to　study　adaptability　and　recovery　capability　of　high-efficiency　denitrifying　bacteria　and　their　embedding　filler　to　low　temperature　and　low　substrate　concentration,　a　test　was　performed　under　two　conditions　(favorable　and　unfavorable)　and　three　stages　(D1,　D2,　and　D3)　to　explore　the　denitrifying　capability　of　the　bacteria.　The　favorable　condition　was　a　reacting　temperature　of　30,　a　nitrate　concentration　of　300　mg·L-1,　and　a　C/N　ratio　of　10;　and　the　unfavorable　condition　was　a　reacting　temperature　of　4,　a　nitrate　concentration　of　30　mg·L-1,　and　a　C/N　ratio　of　5.　In　stage　D1,　high-efficiency　denitrifying　bacteria　[300　mg·(L·h)-1],　which　were　cultured　at　favorable　condition,　were　placed　under　the　unfavorable　condition.　In　stage　D2,　the　bacteria　were　embedded　after　the　denitrifying　performance　was　stable,　and　then　this　embedded　filler　was　placed　under　the　unfavorable　condition　and　recovered　in　the　favorable　condition　(D3)　after　90　days.　The　results　show　that　the　denitrification　rates　of　stages　D1　and　D2　finally　stabilized　at　5.4　mg·(L·h)-1　and　4.8　mg·(L·h)-1,　respectively,　after　operation　for　17　d　and　16　d,　indicating　that　the　bacteria　and　their　embedding　filler　adapted　to　the　unfavorable　conditions　of　low　temperature　and　low　substrate　concentration.　In　stage　D3,　the　denitrifying　rate　of　the　filler　reached　300　mg·(L·h)-1　after　operation　for　only　12　d,　indicating　that　the　filler　had　rapid　self-recovery　capability.　Scanning　electron　microscopy　(SEM)　was　utilized　to　analyze　the　internal　and　external　structures　of　the　embedding　filler　and　it　was　determined　that　both　the　internal　and　external　structures　were　favorable　for　bacterial　growth　metabolism　and　mass　transfer.　The　high-throughput　sequencing　analysis　results　show　that　the　dominant　genera　in　stage　D2　were　still　Pseudomonas,　Thauera,　and　Gelidibacter,　which　have　denitrifying　functions,　thereby　indicating　adaptability　of　the　bacteria　under　the　unfavorable　condition.　The　dominant　genera　Thauera,　Petrimonas,　and　Pseudomonas　of　the　embedding　filler　in　stage　D3　were　identical　to　the　dominant　genera　of　the　high-efficiency　denitrifying　bacteria　cultured　under　the　initial　favorable　condition,　which　also　showed　that　the　bacteria　embedding　filler　had　good　recovery　capability.　©　2017,　Science　Press.　All　right　reserved.