A novel enzymatic nanocomposite membrane prepared from functionalized Fe3O4 dip-coated membrane and covalently immobilized lipase
Paper ID : 1105-MST2015-FULL
Marzieh Aghababaie *1, Amir Razmjou2
1department of biotechnology, faculty of Advanced science and technology, University of Isfahn
2biotechnology department, faculty of advance science and technologies, university of Isfahan
Membrane-immobilized enzymes have received an increasing attention in biosensors, enzyme reactors and membrane bioreactor which can be used in different industries.

In this study, lipase from Candida rugosa was covalently immobilized on Fe3O4 nano-particles dip-coated commercial Ultrafiltration Membrane. Initially, the silica coated Fe3O4 nano-particles were dip-coated on the membrane surface via a low temperature hydrothermal process, and then aminated with 3-aminopropyletriethoxysilane (APTES). Glutaraldehyde was used as a coupling agent to covalently immobilize lipase on the nanocomposite membrane surface. Various techniques such as SEM, FTIR, TGA, AFM, contact angle goniometry and surface free energy measurement were used to characterize the enzymatic nanocomposite membrane.

The results showed that the immobilization process was successful in terms of enzyme activity and immobilization efficiency. It was found that the functionalized dip-coated membrane greatly improved the relative activity and loading capacity by 49% and 15%, respectively, in comparison to unmodified membrane. The kinetic constant of free lipase and immobilized lipase determined to investigate the effect of immobilization on nanocomposite membrane. The Km value decreased from 0.2 mM for free lipase to 0.15 mM for immobilized lipase which showed higher affinity of immobilized lipase. The results also showed that the maximum reaction rate has significantly increased as Vmax rose from 3649 to 14705 mM/cm2.min for free and immobilized lipase, respectively, due to more efficient conformation of immobilized lipase. This enzymatic nanocomposite membrane showed higher thermal, pH and storage stability than free form of enzyme as well. The prepared enzymatic nanocomposite membranes have a great potential to be used as a promising alternative in bio-catalytic processes.
Enzymatic nanocomposite membrane, lipase, enzyme immobilization, membrane functionalization, magnetic nanoparticle
Status : Paper Accepted (Oral Presentation)