Polyaniline-Functionalized Magnetic Mesoporous Nanocomposite: A Smart Material for the Immobilization of Lipase

Magnetically separable mesoporous silica nanocomposites with polyoaniline functionalization (Pani-MS@Fe3O4) were synthesized for the immobilization of lipase via electrostatic adsorption. The as-prepared PaniMS@Fe3O4 nanocomposites as well as immobilized lipase were characterized by FTIR, XRD, HRTEM, FESEM, BET, and TGA techniques. The BET surface area was calculated to be 779.27 m(2)/g, 425 m(2)/g, and 230.45 m(2)/g for magnetic mesoporous nanoparticle (MS@Fe3O4), PaniMS@Fe3O4 nanocomposite, and lipase immobilized PaniMS@Fe3O4 nanocomposite respectively. The comparison experiments verified that the immobilized lipase exhibited slightly higher optimal pH and temperature value with a wider pH-activity and temperature stability in comparison with the free lipase. From Michaelis-Menten kinetic study, the lower K-m value (0.25 mM) and higher V-max value (0.0341 mM/min) for the immobilized lipase revealed the higher affinity of immobilized lipase toward the substrate. Further, reusability studies of the immobilized lipase indicated that up to 70% of the original activity was retained after having been recycled seven times. (C) 2014 Society of Plastics Engineers