Immobilization of Pseudomonas cepacia lipase on layered double hydroxide of Zn/Al-Cl for kinetic resolution of rac-1-phenylethanol.

Layered double hydroxides (LDHs) are cheap materials suitable for immobilization of enzymes. In this study, we prepared Zn/Al-Cl LDHs with different Zn:Al molar ratios for immobilization of the lipase from Pseudomonas cepacia. The best values for activity retention (188%), immobilization efficiency (96%) and hydrolytic activity in organic medium (279 U g-1) were obtained with a molar ratio of Zn:Al of 4:1, a protein loading of 162 mg g-1 and Tris-HCl buffer (10 mmol L-1, pH 7.5) as the solvent for preparing the lipase solution. The immobilized lipase keeps its activity when stored at 4 °C during 30 days. The immobilized lipase gave a conversion of 50% in 1 h for the kinetic resolution of the alcohol rac-1-phenylethanol, with both ees and eep higher than 99% and E higher than 200. In the reutilization study, 30 successive 1-h kinetic resolutions were done with the same batch of immobilized enzyme. For all 30 resolutions, 50% conversion was maintained, with ees and eep higher than 99% and E higher than 200. These are promising results that lay the basis for further studies of immobilization of lipases onto LDHs for applications in organic media.