Immobilization β-glucosidase from Dictyoglomus thermophilum on UiO-66-NH2: An efficient catalyst for enzymatic synthesis of kinsenoside via reverse hydrolysis reaction

Kinsenoside is a rare and valuable glycoside with extensive bioactivities. However, the enzymatic synthesis of kinsenoside has been a challenging task due to the limited enzyme toolbox and unsatisfactory yield. Herein, the β-glucosidase from Dictyoglomus thermophilum (DtBGL) was heterologously expressed, purified and enzymatically characterized. The purified DtBGL was successfully immobilized on the metal-organic frameworks of UiO-66-NH 2 . The DtBGL@UiO-66-NH 2 was fully characterized using SEM, XRD, TGA and FTIR. The studies on enzymatic properties demonstrated that DtBGL@UiO-66-NH 2 exhibited increased catalytic activity and stability compared to the free DtBGL. Particularly, DtBGL@UiO-66-NH 2 could catalyze the synthesis of kinsenoside via the reverse hydrolysis reaction and the kinsenoside yield was 34.12 % under the optimized catalytic system, which was 1.9-fold higher compared with the free DtBGL. Moreover, DtBGL@UiO-66-NH 2 displayed good reusability with a kinsenoside yield of 27.02 % after reuse for 3 times. The present work not only identifies and characterizes a highly active β-glucosidase with reverse hydrolysis activity, but also proposes the immobilized enzyme as an effective catalyst for the industrial production of glycosides.