Dual-mechanism defect engineering of multi-enzyme embedded ZIF-8 for efficient anthocyanin extraction from black rice

Anthocyanins are promising natural antioxidants widely present in plants. While enzymatic catalytic hydrolysis is a feasible strategy for the extraction of bioactive compounds from plants, the limited stability of free enzymes poses a significant challenge to this approach. Enzyme immobilization using zeolitic imidazolate framework-8 (ZIF-8) demonstrates considerable potential for improving enzymatic tolerance. However, enzyme@ZIF-8 encounters challenges due to reduced bioactivity, primarily attributed to the microporous structure of ZIF-8. To address these limitations, defect-induced mesopores are created in multi-enzyme@ZIF-8 through in-situ millifluidic synthesis, followed by UV post-treatment to introduce additional surface defects. These multi-enzyme@ZIF-8/UV nanoparticles adhere to black rice powder via electrostatic interactions, thereby facilitating the cell wall breakdown. The anthocyanin extraction yield of multi-enzyme@ZIF-8/UV reaches 10.76 mg/L, representing a 31.7 % increase compared to multi-enzyme@ZIF-8 without UV post-treatment. This study provides defect-engineered porous ZIF-8 biocomposites that simultaneously enhance the stability and catalytic activity of encapsulated enzymes for efficient extraction of plant-derived polyphenolic flavonoids, demonstrating broad potential in sustainable biocatalysis and natural product recovery.