Core-shell covalent organic framework immobilized β-lactamase for continuous and eco-friendly degradation of antibiotics in wastewater.

The environmental residues of penicillin antibiotics and their induced spread of resistance genes pose a serious challenge to global public health and ecological safety. Conventional wastewater treatment technologies face challenges in meeting current demands due to their suboptimal efficiency and the potential for secondary contamination. In this study, a covalent organic framework (COF)-based enzyme immobilization strategy was designed to construct a composite biocatalyst (β-Lac@Tp-Pa) through dynamic Schiff base condensation, which covalently anchored β-lactamase onto the imine COF (Tp-Pa) backbone, developing an enzyme core-COF shell structure that integrates enzymatic functionality with framework stability. The preparation conditions for β-Lac@Tp-Pa were systematically optimized. Under the optimal conditions, an enzyme activity recovery rate of 36.8% was achieved, while the enzyme leaching rate during recycling was maintained below 10%. In conjunction with a recirculating flow reaction device, approximately 99% removal of 50-200 mg L-1 penicillin in filtered lake water was achieved. Additionally, it demonstrated a retention of approximately 60% of its initial activity after twenty cycles. This study demonstrates the potential application of enzymes encapsulated in covalent organic frameworks in the field of wastewater treatment, providing a valuable reference for research in this area.