Stereoselective ring-opening of styrene oxide at elevated concentration by Phaseolus vulgaris epoxide hydrolase, PvEH2, in the organic/aqueous biphasic system.

Abstract To elevate the concentration of racemic styrene oxide (rac -SO), its asymmetric hydrolysis in organic/aqueous biphasic system was researched. Firstly, n -octane/phosphate buffer reaction system was constructed, where Pv EH2 retained 75.9% activity at 25 °C for 8 h. Secondly, the optimal volume ratio of two phases and weight ratio of rac -SO to E. coli / pveh2 were 4:6 and 0.8. Then, the maximum allowable rac -SO concentration was assayed as 200 mM, 10-fold that in aqueous phase. Finally, the hydrolysis of rac -SO was performed, affording (R)-SO with over 99.5% ee s and 47.8% yield, and (R)-phenyl-1,2-ethanediol with 93.6% ee p and 50.4% yield in 12 h. Graphical abstract Unlabelled Image Highlights • Pv EH2 was more stable in long-chain alkanes than in alcohols. • Racemic styrene oxide (rac -SO) was hydrolyzed in n -octane/aqueous system by Pv EH2. • The rac -SO concentration in biphasic system was 10-fold that in single aqueous phase. • (R)-SO with >99.5% ee s and (R)-phenyl-1,2-ethanediol with 93.6% ee p were coproduced. • The volumetric productivity of (R)-SO (0.96 g/L/h) was the highest ever reported. [ABSTRACT FROM AUTHOR]