One-step purification and immobilization of UDP-glycosyltransferase with modified Fe3O4 for the synthesis of ginsenoside Rh2

The disadvantages of high purification cost and difficult reuse of free enzymes restrict their application in the green biochemical industry, and immobilized enzymes with good performance are the necessary conditions for their industrialization. To reduce the cost of separation and purification of UDP-glycosyltransferase (UGT)in the catalytic synthesis of ginsenoside Rh2 and to overcome the problem of the inability to reused free enzyme, a magnetic Fe3O4/MPN-Ni2+ material was synthesized to purify while immobilizing recombinant UGT. The resulting immobilized enzyme could be quickly separated from the reaction for reuse. It is proved that the immobilized material has a specific adsorption effect on UGT, and the immobilized enzyme (Fe3O4/MPN-Ni2+@UGT) has a high enzyme load (100.91 mg/g) and stability. The immobilized enzyme still maintains 65.07% activity after 6 cycles. After 21 days of storage, its activity is still 54.01%. Under the optimal conditions, the immobilized enzyme can catalyze the synthesis of Rh2 at 40.73 μg/mL and the conversion rate of protopanaxadiol (PPD) is 70.88%. This lowcost, efficient and stable material has great potential and value for industrial application in enzyme purification and synthesis of ginsenosides.