Improved synthesis of long-chain alkyl glucosides catalyzed by an engineered β-glucosidase in organic solvents and ionic liquids.

Objective: To synthesize octyl β-D-glucopyranoside (OG) and decyl β-D-glucopyranoside (DG) in three non-aqueous reaction systems, namely organic solvents, ionic liquids and co-solvent mixtures, via reverse hydrolysis reactions catalyzed by the N189F dalcochinase mutant.

Results: The highest yield of OG (67 mol%) was obtained in the reaction containing 0.5 M glucose, 3 unit ml enzyme in 20% (v/v) octanol and 70% (v/v) [BMIm][PF] at 30 °C. On the other hand, the highest yield of DG (64 mol%) was obtained in the reaction containing 0.5 M glucose, 3 unit ml enzyme in 20% (v/v) decanol, 20% (v/v) acetone and 50% (v/v) [BMIm][PF] at 30 °C. The identities of OG and DG products were confirmed by HRMS and NMR.

Conclusion: This is the first report of enzymatic synthesis of OG and DG via reverse hydrolysis reactions in ionic liquids and co-solvent mixtures. The N189F dalcochinase mutant and the non-aqueous reaction systems described here show great potential for future commercial production of long-chain alkyl glucosides.