Ionic Liquid Effects on the Activity of β-Glycosidase for the Synthesis of Salidroside in Co-solvent Systems

The preparation of salidroside was successfully carried out in fourteen ionic liquids (ILs)-containing systems using beta-glycosidase from black plum seeds for the first time. The optimum conditions were determined for C(6)MIm center dot BF4, pH, phosphate buffer content, and molar ratio of tyrosol to D-glucose to be 1% (v/v), 5.9, 20% (v/v), and 8:1, under which the initial reaction rate and yield were 3.3 mmol/(L.h) and 24.5%, respectively. Moreover, the effects of 1-alkylimidazolium-based ILs possessing different alkyl chain lengths from C-2 to C-10 and a variety of anions including BF4-, PF6-, Cl-, Br-, and I- on enzyme activity in co-solvent systems were investigated. The results indicate that the optimal chain length of the alkyl substituent on the imidazolium ring of the cation was C-6.