Influence of differently modified palygorskites in the immobilization of a lipase

Lipase, a commercial enzyme, was immobilized onto three different modified palygorskite supports. The palygorskites were modified either by acid treating, or reacting the surface silanol groups present with 3-aminopropyltriethoxysilane, or treating with a quaternary ammonium compound (octodecyl trimethyl ammonium chloride), to produce derivatives with suitable functional group for further utilization in the immobilization of enzyme. The natural palygorskite and their derivatives used were characterized with regard to infrared spectroscopy (FTIR), X-ray diffraction (XRD), surface area and differential scanning calorimetry thermo-gravimetric analysis (DSC–TGA). The amount of lipase adsorbed was much larger on the palygorskite modified by octodecyl trimethyl ammonium chloride (POTMAC) than that on the acid activated palygorskite (Pa) and the palygorskite modified by 3-aminopropyltriethoxysilane (PAPTES). The amount of lipase adsorbed on the Pa was a little smaller than on the PAPTES. The enzyme activity and activity recovery in the hydrolysis of olive oil was compared. And, the PAPTES showed the highest enzyme activity and activity recovery in the hydrolysis of olive oil. The enzyme activity and the activity recovery of lipase immobilized on PAPTES was 27.24 U/g and 19.43%, respectively.