Bubble-enhanced micromixing in an enzyme/MnO2 system immobilized in a covalent organic framework for boosting enzymatic catalysis

Mass transfer limitations severely constrain the catalytic efficiency of immobilized enzymes. This study presents a bubble-enhanced micromixing strategy utilizing a covalent organic framework (COF) co-encapsulating β-glucosidase and MnO 2 nanozymes. MnO 2 catalyzes H 2 O 2 decomposition to generate oxygen microbubbles, inducing localized microconvection that disrupts diffusion boundary layers without external energy input. The E-MnO 2 @COF system with 5% H 2 O 2 achieved 98.31% of the free enzyme activity, markedly surpassing the catalytic activities of static E@COF (17.97%) and magnetically stirred controls (90.28%). Kinetic analysis revealed substantially reduced apparent K m and elevated V max , confirming enhanced substrate affinity and active site accessibility. The composite retained 76.25% of its initial activity after 10 cycles and exhibited notable solvent tolerance. This approach offers an efficient, sustainable solution for overcoming diffusion constraints in heterogeneous biocatalysis.