Enzyme immobilized millimeter-sized polyHIPE beads with easy separability and recyclability

Enzyme functionalized porous beads were fabricated through covalently immobilizing Candida antarctica lipase B (CALB) onto high internal phase emulsion (HIPE) templated poly(glycidyl methacrylate) (PGMA) beads. These millimeter-sized beads were prepared by photopolymerizing the continuous phase of HIPE drops and then removing the dispersed phase. By covalently coupling the lysine residues of CALB to the epoxy groups from GMA, a series of enzyme immobilized polyHIPE beads were produced, with an enzyme loading of up to 0.18 g g−1 carrier. The resulting immobilized enzyme was highly stable to temperature and storage and could be recycled multiple times. The immobilized enzyme maintained 85% residual activity after 5 reaction cycles and 60% residual activity after 30 days of storage. The enzymatic esterification between hexanol and hexyl hexanoate had a conversion rate of up to 95%, showing that the enzyme immobilized beads were a good enzyme catalyst.