Immobilization of Enzymes on Cyclodextrin-Anchored Dehiscent Mesoporous TiO2 for Efficient Photoenzymatic Hydroxylation

A three-in-one heterogeneous catalyst (UPO@dTiO2-CD) was fabricated by grafting cyclodextrins (CDs) on the dehiscent TiO2 (dTiO2) surface and subsequently immobilizing unspecific peroxygenase (rAaeUPO), which exhibited double enhanced electron/mass transfer in photo-enzymatic enantioselective hydroxylation of the C-H bond. The tunable anatase/rutile phase ratio and dehiscent mesoporous architectures of dTiO2 and the electron donor feature and hydrophobic inner cavity of the CDs are independently responsible for accelerating both electron and mass transfer. The coordination of the photocatalytic and enzymatic steps was achieved by structural and compositional regulation. The optimized UPO@dTiO2-CD not only displayed high catalytic efficiency (turnover number and turnover frequency of rAaeUPO up to >65,000 and 91 min-1, respectively) but also exhibited high stability and reusability.