Preparation, functionalization and characterization of rice husk silica for lipase immobilization via adsorption

Publication date: Available online 3 May 2019Source: Enzyme and Microbial TechnologyAuthor(s): Natália B. Machado, João P. Miguez, Iara C.A. Bolina, Adriana B. Salviano, Raphael A.B. Gomes, Olga L. Tavano, Jaine H.H. Luiz, Paulo W. Tardioli, Érika C. Cren, Adriano A. MendesAbstractSilica has been extracted from rice husks via a simple hydrothermal process and functionalized with triethoxy(octyl)silane – OCTES (Octyl–SiO2) and (3-aminopropyl)triethoxysilane – 3-APTES (Amino–SiO2), with the aim of using it as support to immobilize lipase from Thermomyces lanuginosus (TLL) via adsorption. The supports have been characterized by particle size distribution and elemental analyses, XRD, TGA, SEM, AFM and N2 physisorption so as to confirm their functionalization. Effect of pH, temperature, initial protein loading and contact time on the adsorption process has been systematically evaluated. Maximum immobilized protein loading of 12.3 ± 0.1 mg/g for Amino–SiO2 (5 mM buffer sodium acetate at pH 4.0, 25 °C and initial protein loading of 20 mg/g) and 21.9 ± 0.1 mg/g for Octyl–SiO2 (5 mM buffer sodium acetate at pH 5.0, 25 °C and initial protein loading of 35 mg/g) was observed. However, these biocatalysts presented similar catalytic activity in olive oil emulsion hydrolysis (between 630 and 645 U/g). TLL adsorption was a spontaneous process involving physisorption. Experimental data on Octyl–SiO2 and Amino–SiO2 adsorption were well-fitted to ...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research