Multipoint covalent immobilization of lipases on aldehyde-activated support: Characterization and application in transesterification reaction

This work describes a process of multipoint covalent immobilization of the lipases from Rhizomucor miehei (RML) and type B from Candida antarctica (CALB) in modified Immobead 150 support. Acid hydrolysis, followed by oxidation with sodium periodate, was applied to modify Immobead 150 by exchanging its epoxy groups to aldehyde in its surface. Immobilization occurred between the introduced aldehyde groups on the support and the primary amino groups from the lysines on the enzyme surface. These biocatalysts were characterized using the techniques of Fourier Transform Infrared Spectroscopy: Attenuated Total Reflectance (FTIR-ATR), Thermogravimetric Analysis (TGA), Differential Thermogravimetry (DTG) and used for the transesterification reaction of soybean oil. The immobilization was highly efficient, 96.30% and 99.08% for CALB and RML, respectively, with yields of 86.68% to CALB and 94.21% to RML. Analysis of the enzymatic transesterification reaction between soybean oil and methanol showed that the CALB preparation presented higher yield (72%) of fatty acid methyl ester than RML (29%) in 4 h. These results show the possibility to obtain immobilized derivatives with important properties to be used in further studies to optimize biodiesel synthesis.