Polyaniline‐functionalized magnetic mesoporous nanocomposite: A smart material for the immobilization of lipase

Magnetically separable mesoporous silica nanocomposites with polyoaniline functionalization (Pani‐MS@Fe 3 O 4 ) were synthesized for the immobilization of lipase via electrostatic adsorption. The as‐prepared Pani‐MS@Fe 3 O 4 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@Fe 3 O 4 ), Pani‐MS@Fe 3 O 4 nanocomposite, and lipase immobilized Pani‐MS@Fe 3 O 4 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. POLYM. COMPOS. 37:1152–1160, 2016. © 2014 Society of Plastics Engineers