Competition between transglycosylation and hydrolysis in almond β-glucosidase-catalyzed conversion of p-nitrophenyl-β-d-glucoside in monophasic water/alcohol mixtures

Abstract

Almond β-glucosidase was used to catalyze the transglycosylation of p-nitrophenyl-β-d-glucoside to alkyl glucosides, with hydrolysis to glucose as a side reaction. The conversions were carried out in alcohols with varying water contents below water saturation. Both the total reaction rate and the ratio between the transglycosylation and hydrolysis increased with increasing water activity, and at a fixed water activity in the different alcohols, rate and transglycosylation/hydrolysis ratio increased in the following order: 1-octanol<1-hexanol<1-butanol. Synthesis of alkyl glucosides by transglycosylation in monophasic alcohol media is thus most favorable for short chain alcohols, and should be carried out at high water content.