One-dimensional covalent organic framework as a robust carrier for enhanced lipase immobilization and catalytic performance

Enzymes catalyze stereoselective transformations under mild conditions, yet their industrial deployment remains constrained by intrinsic fragility, poor recyclability, and prohibitive cost. While immobilization on solid carriers can circumvent these limitations, conventional methods suffer from enzyme leaching or diffusional barriers. Covalent organic frameworks (COFs) offer an ideal solution by combining high surface area, tunable pore environments, and robust covalent linkages; however, the narrow pore apertures of conventional two-/three-dimensional scaffolds (< 2 nm) preclude efficient loading of enzymes whose hydrodynamic diameters typically exceed 5 nm. Here we demonstrate that a one-dimensional, pyrene–phenanthroline COF (PhenCOF) overcomes this steric mismatch by presenting densely distributed, surface-exposed imine groups that serve as anchoring points for covalent enzyme attachment. Candida antarctica lipase B (CALB) was immobilized via an Ugi-type three-component reaction to afford CALB@PhenCOF. The resultant hybrid exhibits exceptional catalytic performance in kinetic resolution of racemic 1-phenylethanol, achieving 99% conversion, 2.4-fold higher than free CALB. The 1D architecture and hydrophobic microenvironment facilitate substrate diffusion while stabilizing the enzyme's active conformation, as evidenced by retention high activity under wide pH ranges, extreme organic solvents, and temperatures up to 140°C. Notably, covalent immobilization endows unparalleled recyclability, with 95% efficiency maintained over 10 cycles. This work establishes 1D COFs as a paradigm for promising enzyme carriers, merging atomic precision with industrial robustness to address longstanding challenges in biocatalysis.