Covalent Organic Framework Nanosheets for the Assembly of Efficient Membrane Bioreactors

Immobilizing fragile enzymes in porous materials holds significant potential for biocatalysis but encounters challenges such as mismatched enzyme size and pore structure of host materials, along with harsh assembly conditions that can denature enzymes. Herein, we present a versatile strategy for constructing membrane bioreactors through water-mediated, vacuum-assisted layer-by-layer assembly of covalent organic framework (COF) nanosheets with enzymes. This method effectively addresses pore size limitations, preserves enzyme activity, and promotes convective transport of reactants to active sites, while shielding enzymes from harmful by-products through rapid transport in continuous membrane catalysis. The optimized bioreactor achieves a 1018-fold increase in relative activity compared to free enzymes in batch reactions, completing substrate conversion in just 7.95 s, and demonstrating enhanced stability.