Evaluation of Candida rugosa Lipase Immobilized on Magnetic Nanoparticles in Enzymatic/Chemical Hydroesterification for Biodiesel Production

Abstract

This study aimed to (i) prepare functionalized maghemite nanoparticles for immobilization of Candida rugosa lipase (CRL) by covalent binding, (ii) evaluate the application of the immobilized derivative in the hydrolysis of waste cooking oil (WCO) to fatty acids, and (iii) assess the potential of the hydrolyzed material for biodiesel production by hydroesterification. Maghemite (γFe2O3) obtained by precipitation of Fe3Cl2 with NH4OH served as an efficient support for covalent immobilization of CRL. Fourier-transform infrared spectroscopy and hydrolytic activity analysis indicated that CRL was covalently immobilized on the surface of the maghemite support. The derivative showed an activity of 166.62 ± 8 U g−1 in WCO hydrolysis at 40 °C and pH 6. Scanning electron microscopy revealed that, after lipase immobilization, nanoparticles became more dispersed, which is advantageous for biocatalysis reactions, as it increases the contact area with the substrate. WCO hydrolysis afforded 96 ± 0.2 wt% free fatty acids. In the second step, free fatty acids were subjected to chemical esterification with sulfuric acid, affording 94.4 ± 0.02 wt% fatty acid methyl esters (biodiesel). The findings of this study contribute to the field of biotechnology and may promote the development of enzymatic technologies for the synthesis of products of economic and social interest.