The effect of deep eutectic solvents on the asymmetric hydrolysis of styrene oxide by mung bean epoxide hydrolases

Abstract

Abstract Background Deep eutectic solvents have attracted considerable attention in numerous fields. There is little information on mung bean epoxide hydrolase-catalyzed epoxides in deep eutectic solvent-containing system. Results Adding deep eutectic solvents with hydrogen bond donor of acids to phosphate buffer resulted in an obvious decrease in the optical purity of product; nevertheless, the relative slight change was observed by the addition of the deep eutectic solvents with hydrogen bond donor of alcohols and urea. Of the tested deep eutectic solvents, 10% additional amount of choline chloride/trithylene glycol can cause a significant improvement in the enantiopurity of product, from 83.2 ± 1.3% to 87.9 ± 0.3%. Moreover, with the increase in the addition amount of choline chloride/triethylene glycol from 10 to 30%, the enantiomeric excess of product enhanced from 87.9 to 94%, but a decline of product yield was observed. Finally, the evaluation of enzyme stability showed that the additional amount from 10% to 30% was not beneficial to the activity recovery. Conclusion In short, adding choline chloride/triethylene glycol contributes to the improvement in the optical purity of (R)-1-phenyl-1, 2-ethanediol in the catalysis of styrene oxide by mung bean epoxide hydrolases; meanwhile, the enzyme immobilization could be essential.

Keywords

• Deep eutectic solvents
• Epoxide hydrolase
• Styrene oxide
• 1-Phenyl-1,2-ethanediol