Glu@Zn‐Ni MOF Constructed Through Ligand Exchange for Bi‐Enzyme Immobilization With Improved Performance in Rare Ginsenoside Production

Abstract

The biological conversion method using immobilized enzymes has become an important means to produce ginsenosides. Among them, the preprepared Zn‐Ni MOF could be used to immobilize glycosyltransferase by specific adsorption for ginsenoside Rh2 production. However, the low enzyme load of Zn‐Ni MOF limited its wide application. In this study, we successfully synthesized the Glu@Zn‐Ni MOF filled with nanospheres by modifying the previously prepared Zn‐Ni MOF with glutamic acid (Glu) through ligand exchange. This modification significantly increased the specific surface area of the Glu@Zn‐Ni MOF and enhanced the material's enzyme‐carrying capacity. After immobilizing glycosyltransferase (UGT) onto the Glu@Zn‐Ni MOF, the UGT@Glu@Zn‐Ni MOF demonstrated improved stability across different pH levels, temperatures, and repeated cycles. After seven cycles, the immobilized enzyme remained at 83.42% of its initial enzyme activity. To further enhance the process, we incorporated immobilized sucrose synthase into the system to form a coupled reaction. This approach not only reduced substrate costs but also increased the yield of ginsenoside Rh2. By optimizing the coupling reaction through adjustments to the reaction conditions and the addition of suitable surfactants and organic solvents, we achieved a yield of 5.41 μg/mL of Rh2. The development and optimization of this material hold significant potential and value for industrial applications in both material enhancement and ginsenoside synthesis.