Morphology engineering of ZIF-8 supported biocatalyst: comparative performance in three model reactions

Rational engineering of nanocarrier morphology is pivotal for enhancing both the activity and recyclability of immobilized lipases. Although zeolitic imidazolate framework-8 (ZIF-8) represents a leading scaffold for enzyme immobilization, its morphology-dependent conjugation behavior toward lipases remains unexplored. Herein, we prepared five distinct ZIF-8 nanostructures-rhombic dodecahedral (RD), truncated rhombic dodecahedral (TRD), rough rhombic dodecahedral (RRD), flower-like, and flake-like structures. Three lipases (PS, CALB, and AY400SD) were subsequently immobilized to generate a 15-member library. Systematic evaluation demonstrated that carrier morphology plays an important role in biocatalytic performance: PS@ZIF-8-RRD achieved >49% conversion with >99% ee_s during the kinetic resolution of 1-phenylethanol; CALB@ZIF-8-TRD yielded 92% conversion in the solvent-free esterification between caproic acid and ethanol; AY400SD@ZIF-8-RD approached free enzyme activity levels in perilla seed oil hydrolysis within biphasic media. Such morphology-activity relationships arise from facet-dependent enzyme orientation and tailored microenvironments.