Immobilization of Pectinase Enzyme on Hydrophilic Silica Aerogel and Its Magnetic Nanocomposite

in this work, Aspergillus niger pectinase was immobilized on hydrophilic silica aerogel and its magnetic nanocomposite by adsorption method, and the performance of these supports in pectinase immobilization was compared. Physical and chemical properties of supports and the immobilized pectinase were characterized by Brunauer–Emmett–Teller (BET) analysis, Field Emission Scanning Electron Microscope (FESEM), Fourier Transforms InfraRed (FT-IR) spectroscopy, and Vibrating Sample Magnetometer (VSM). The results showed that the pectinase was successfully immobilized onto both supports. The kinetics of the immobilized pectinase followed Michaelis–Menten model. The maximum reaction rate (Vmax) and affinity of immobilized pectinase to the substrate (Km) in pure silica aerogel were higher than in magnetic silica aerogel. The maximum monolayer adsorption capacity of the pure silica aerogel (qmax=129.17 mg/g) was higher than magnetic silica aerogel (qmax=53.42 mg/g) based on Langmuir isotherm. The thermal stability of the immobilized pectinase was improved toward free pectinase. The reusability tests of immobilized pectinase showed that magnetic silica aerogel had better operational stability than pure silica aerogel because of higher mechanical resistance and retained 57% of its initial activity after 10 repetitive cycles.