Abstract:
The Fe3O4 magnetic nanoparticles were prepared by precipitating ferrous ion (Fe2+) and ferric ion (Fe3+) in alkaline solution. The Fe3O4 magnetic nanoparticles were modified by tannic acid. After functionalization process, two methods were used to immobilize Lipase on Fe3O4 magnetic nanoparticles. In the first method, novel tannic acid magnetic cross-linked enzyme aggregates of lipase (TA-MNPs-CLEAs) were synthesized by cross-linking of lipase aggregates and starch as co-feeder with Fe3O4 magnetic nanoparticles improved by tannic acid (TA-MNPs). In the second method, the lipase was successfully immobilized on the surface of TA-MNPs. The properties of Fe3O4 and its modified forms were examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and zeta potential measurements. Novel TA-MNPs-lipase and TA-MNPs-CLEAs-starch-lipase were enhanced and provided an effective method to improve the activity and stability of lipase for biodiesel production. Using 1% TA-MNPs-lipase and TA-MNPs-CLEAs-starch (w/w of oil) conversions around 67.87, and 85.88%, respectively, were obtained at 40 degrees C after 2 h of reaction. Furthermore, the immobilized enzyme was easily recovered from the reaction mixture and reused. The obtained results suggest that TA-MNPs-lipase and TA-MNPs-CLEAs-starch-lipase can become a powerful biocatalyst for biodie-sel production. (C) 2018 Elsevier B.V. All rights reserved.
