A　bioactive　covalent　organic　framework(bio-COF)　capsuleis　fabricated　through　enzyme-induced　growth　and　crystallization　ofCOFs　on　a　sacrificial　template　for　sustainable　lactate　synthesis.　Capsular　covalent　organic　frameworks　(COFs)　offer　uniqueand　highlytunable　spaces　for　enzyme　immobilization.　Herein,　a　kind　of　bioactivecovalent　organic　framework　(bio-COF)　capsule　was　fabricated　througha　sacrificial　templating　method　for　the　synthesis　of　lactate　frompyruvate.　The　synthesis　time　of　COF　and　the　amount　of　enzyme　wereoptimized　during　the　preparation　of　bio-COF　capsules.　The　enzymeswere　entrapped　in　the　capsule　wall　with　a　thickness　of　similar　to　240nm　and　a　major　pore　size　of　similar　to　1.8　nm.　The　porous　structure　ofbio-COF　capsules　ensured　rapid　diffusion　of　substrates　through　thecapsule　wall.　Thereby,　the　bio-COF　capsule　retained　70%　of　its　initialactivity　under　reaction　conditions　at　pH　6　and　35　degrees　C.　The　confinementof　the　capsule　wall　toward　enzymes　remarkably　improved　the　operationalstability　and　organic　solvent　tolerance.　After　treatment　under　pH4　and　60　degrees　C　for　120　min,　the　bio-COF　capsules　still　retainedthe　relative　activities　of　79　and　60%,　respectively.　Furthermore,the　bio-COF　capsules　exhibited　superior　recyclability,　retaining　over85%　relative　activity　after　8　cycles.　Our　study　offers　a　general　platformfor　immobilizing　enzymes　and　expands　the　potential　application　ofCOFs　in　the　green　biomanufacturing　field.