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.
Subject(s)
Lipase , Magnetite Nanoparticles , Lipase/chemistry , Enzymes, Immobilized/chemistry , Biofuels , Enzyme Stability , Magnetite Nanoparticles/chemistry , Fatty Acids, Nonesterified , Candida , Temperature , Esterification , Biocatalysis , Sulfuric AcidsABSTRACT
In this study, trypsin (Enzyme Comission 3.4.21.4) was immobilized in a low cost, lignocellulosic support (corn cob powder-CCP) with the goal of obtaining peptides with bioactive potential from cheese whey. The pretreated support was activated with glyoxyl groups, glutaraldehyde and IDA-glyoxyl. The immobilization yields of the derivatives were higher than 83%, and the retention of catalytic activity was higher than 74%. The trypsin-glyoxyl-CCP derivative was thermally stable at 65 °C, a value that was 1090-fold higher than that obtained with the free enzyme. The trypsin-IDA-glyoxyl-CCP and trypsin-glutaraldehyde-CCP derivatives had thermal stabilities that were 883- and five-fold higher, respectively, then those obtained with the free enzyme. In the batch experiments, trypsin-IDA-glyoxyl-CCP retained 91% of its activity and had a degree of hydrolysis of 12.49%, while the values for trypsin-glyoxyl-CCP were 87% and 15.46%, respectively. The stabilized derivative trypsin-glyoxyl-CCP was also tested in an upflow packed-bed reactor. The hydrodynamic characterization of this reactor was a plug flow pattern, and the kinetics of this system provided a relative activity of 3.04 ± 0.01 U·g-1 and an average degree of hydrolysis of 23%, which were suitable for the production of potentially bioactive peptides.
