Síntese e caracterização de nanopartículas magnéticas (Fe3O4) e seu uso como suporte para imobilização de lipase Thermomyces lanuginosus (TLL)

Abstract

The immobilization of enzymes in magnetic nanoparticles is a strategy that enables the recovery of conjugated nanoparticles enzymes from the selection of material immobilized by centrifugation or by the application of an external magnetic field. In this context, the present work used the magnetic nanoparticles (Fe3O4) as a support for immobilization of the lipase applied by Thermomyces lanuginosus (TLL). This lipase has important applications in the industry, such as, for example, in the production of biodiesel, pesticides, food, among others. Specifically, in the first stage of the work, it was magnetic nanoparticles (NPM) through the coprecipitation method using sodium hydrogen as a reducing agent. As the NPM were characterized by TEM, AFM, XRD,FTIR, TGA, DLS and potential zeta and results by different techniques used in the treatment of small NPM, for example, the TEM images showed displays of 8.3 ± 2,7 nm, the AFM showing a size of 12,0 ± 2,0 nm and the DLS showing a DH 34,19 ± 0,91 nm, with a load surface varying between + 35,0 mV at pH 3,0 to – 35,0 mV at pH 12,0. A characterization by XRD proven as NPM in the type Fe3O4, by FTIR it was determined the display of captures of the type Fe-O and O-H in material and by TGA it was observed how NPM is the temperature range of 400°C to 900°C. In a second step, the charge surface for the TLL enzyme was computationally evaluated using the information obtained in the PDB, and the differentiation of the electrostatic potential in each region of the macromolecule was verified. Finally, 3 pH control conditions were chosen in order to modify the loading surfaces of the enzyme and NPM and evaluate its adsorption process. Thus, the immobilized material showed 99,49% of the enzyme adsorption to the support, recovering 62,3% of the hydrolytic activity, in relation to the initial activity of the free lipase. And the catalytic efficiency in the synthesis of the ethyl oleate ester was 80% after 12 cycles of reuse.