Chemical modification of clay nanocomposites for the improvement of the catalytic properties of Lipase A from Candida antarctica

Abstract

Kaolin is a mineral composed of hydrated aluminum silicates, clayey and with high bioavailability. The choice of this mineral as immobilization matrix took into account these aspects mentioned above and its high surface area conducive to enzymatic immobilization, containing many OH- binding groups on its surface. Subsequently, the kaolin was functionalized with carboxymethylcellulose and polyethyleneimine (K-CMC-BPEI) and activated with Glutaraldehyde (K-CMC-BPEI-GLU) as a support to immobilize CAL-A. The K-CMC-BPEI-GLU@CAL-A was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TGA), and Scanning Electron Microscopy (SEM). K-CMC-BPEI-GLU@CAL-A, in the temperature range of 50–80 ºC, has a half-life 2–3 times longer than soluble CAL-A, that is, the immobilization process conferred greater stability thermal to the biocatalyst. Furthermore, docking studies showed that the immobilization of CAL-A on the support surface was favorable, since CAL-A has binding affinity to the protein-anchored ligand, estimated at −4.3 to −3.7 kcal/mol. Experiments were performed to verify the catalytic potential of K-CMC-BPEI-GLU@CAL-A at a kinetic resolution of rac-1-(triisopropylsilyl) penta-1,4-diyn-3-ol (1) in an organic medium via an acylation reaction. All experiments yielded the product ((R)-1-Ac) with an excellent enantiomeric excess (ee >99%) and enantioselectivity (E > 200).