The catalytic activity of laccase immobilized onto free and surfactant modified silica aerogel

Abstract

The free silica aerogel (FSA) and surfactant (cetyltrimethylammonium bromide) modified silica aerogel (MSA) were synthesized and used as a support for laccase immobilization. The laccase immobilization onto FSA and MSA was carried out through adsorption process. The laccase concentration was measured using UV-VIS spectrophotometer at wavelength of 280nm. The catalytic activity of free silica aerogel laccase (FSAL) and modified silica aerogel laccase (MSAL) was demonstrated by using 2,2'-Azino-bis(3-ethylbenzoline-6-sulfonic acid)diammonium salt (ABTS) as a substrate. The immobilization was conducted at different parameters such as pH of laccase solutions CTAB concentrations and laccase concentrations. The results show that the MSA performed highe; adsorption of laccase (0.9μmol/g) as compare to FSA (0.3μmollg). In addition, the enhancement of the catalytic activity of the MSAL was also observed and compared to the FSAL. It was found that the laccase catalytic activity of MSAL was 50% higher than FSAL. These results demonstrated that the surface modification of silica aerogel using cationic surfactant (cetyltrimethylammonium bromide) gave higher adsorption capacity and catalytic activity of laccase which can be potentially used for degradation of organic micropollutants such dyes, pesticides and antibiotics.