Study on one-step purification and immobilization of glycosyltransferase by modified Fe3O4 for the synthesis of rare ginsenoside Rh2

Enzymatic catalysis is the most suitable method for synthesizing the ginsenoside Rh2. However, challenges in the purification and reuse of the enzyme limited the applications of this method. In this study, Fe3O4/PMG/NTA-Ni2+ magnetic nanospheres modified with nano-Fe3O4 were employed to achieve the one-step purification and immobilization of glycosyltransferase. The resulting assembly catalyzed ginsenoside protopanaxadiol (PPD) to more valuable Rh2. This material successfully immobilized the recombinant enzyme on the carrier. Moreover, the good dispersibility and superparamagnetism of the immobilized enzyme were maintained without any alteration in its structure, and the maximum immobilized enzyme amount was 180 mg/g. Notably, the pH value, temperature and storage stability of the immobilized enzyme were significantly improved compared with the free enzyme. After reusing the immobilized enzyme six times, the relative enzyme activity was still maintained at 67.8%. Thus, this study specifically adsorbed, purified, and immobilized free glycosyltransferase by modifying nanometer-sized Fe3O4 particles. This reduced operating costs and enhanced the properties of the enzyme.