Lipase B from Candida antarctica Immobilized on Epoxy-functionalized Hollow Silica Microspheres: Efficient Biocatalysts for Enantiomer Selective Acylation of Alcohols and Amines

Abstract

Hollow silica microspheres with promising physical properties (MAT540^TM) as support for enzyme immobilization and biocatalyst were investigated in this study. The amine-functionalized MAT540^TM was activated by six bisepoxides inclosing different spacers and used as epoxy-functionalized carrier for immobilization of lipase B from Candida antarctica (CaLB). The novel, covalently fixed CaLB biocatalysts were compared in kinetic resolution (KR) of racemic 1-phenyethanol rac-1 and five racemic amines rac-3a-e using shaken flasks and continuous-flow packed-bed microreactors. Mechanic stability, re-usability and the effect of temperature (0–90 °C) on productivity and enantiomer selectivity of the covalently immobilized CaLB were investigated. The best performing CaLB biocatalyst showed good mechanic stability after 24 h operation time in continuous-flow mode at 60 °C and provided in KRs of racemic 1-phenyethanol rac-1 with vinyl acetate and of five racemic amines with isopropyl 2-ethoxyacetate as acylating agent the non-reacted (S)-alcohol [(S)-1] or (S)-amines [(S)-3a-e] and the forming (R)-ester [(R)-2] or (R)-amide [(R)-4a-e] in good yields with high enantiomeric excess (ee > 99 %, for all).