Enhanced MOF-immobilized lipase CAL-A with polyethylene glycol for efficient stereoselective hydrolysis of aromatic acid esters

Abstract

Enzyme immobilization is promising in the development of a lipase-catalyzed process for industrial application. The covalent linkage can effectively enhance the interaction between the enzymes and the supports. However, the covalent linkage may reduce the activity of the enzyme. In this work, lipase A from Candida antarctica (CAL-A) was immobilized on a series of MOFs-supports via covalent linkage. The polyethylene glycol (PEG) was surrounded with the CAL-A by the supramolecular interaction for protecting the enzyme activity during the immobilization process thus enhancing the catalytic performance. The optimal immobilized CAL-A was characterized and the catalytic performance was further investigated in lipase catalyzed kinetic resolution of chiral aromatic acids. Benefitting from the stable interaction between the CAL-A and MOF supports and the excellent protection of PEG, the PEG-CAL-A@UiO-66 exhibited enhanced catalytic activity, stability and reusability. The PEG-CAL-A@UiO-66 was applied to stereoselective hydrolysis of 2-phenylbutyric acid isobutyl ester, where yield (YS) and enantiomeric excess (eep) of (S)− 2-PBA reached 91.71% and ＞99.0%, respectively. The loss of enzyme activity after three cycles of reuse was negligible and 47.16% of the initial activity was retained after five cycles of reuse. We believe this effective technique is meaningful for constructing heterogeneous biocatalysts for industrial applications.