Engineering the UiO-66 Surface Microenvironment for Robust β-Glucosidase and Selective Production of Ginsenoside Rd

β-Glucosidases are important biocatalysts for upgrading glycosylated phytochemicals into high-value functional ingredients, but practical bioprocessing is often constrained by insufficient stability and poor substrate selectivity. Herein, a thermostable β-glucosidase (CB-glu) from Caldicellulosiruptor bescii was immobilized on zirconium-based metal–organic frameworks (MOFs) bearing tunable surface functionalities (–H, –NH 2 , –OH, and –2OH). In addition to catalytic characterization, N 2 adsorption–desorption, water-contact-angle, zeta-potential, X-ray photoelectron spectroscopy (XPS), and fluorescence emission analyses were introduced to clarify how carrier physicochemical properties and interfacial microenvironments influence immobilized-enzyme performance. Interfacial analyses showed that CB-glu adsorption reduced the accessible BET area of UiO-66-OH from 1026.4 to 796.7 m 2  g −1 , introduced 11.78 at.% surface N, and occurred despite net-negative zeta potentials of both components, supporting adsorption dominated by interfacial rather than long-range electrostatic interactions. Among the tested supports, UiO-66-OH showed the best compatibility with CB-glu, broadening pH adaptability, improving activity at elevated temperatures, and enhancing tolerance to metal ions and organic solvents. Most importantly, CB-glu@UiO-66-OH selectively hydrolyzed the outer C20-linked glucose of PPD-type ginsenosides and completely converted ginsenosides Rb 1 , Rb 2 , and Rb 3 into ginsenoside Rd without further formation of F 2 or CK. The immobilized biocatalyst maintained 100% conversion over eight consecutive cycles. These findings establish surface-functionalized UiO-66 as a practical microenvironment-engineering platform for regulating β-glucosidase robustness and substrate selectivity, providing a reusable bioprocess for the targeted production of ginsenoside Rd as a high-value functional ingredient.