Immobilization of Candida rugosa Lipase on Glutaraldehyde-Activated Fe3O4@Chitosan as a Magnetically Separable Catalyst for Hydrolysis of Castor Oil

In this study, the catalyzed hydrolysis of castor oil by Candida rugosa lipase (CRL) immobilized on glutaraldehyde-activated magnetic Fe3O4@chitosan is investigated. Magnetic Fe3O4 is prepared by hydrothermal method and coated with chitosan (CS). Next, CRL is immobilized on Fe3O4@chitosan using glutaraldehyde as a cross-linking reagent. The prepared Fe3O4@CS@ CRL is confirmed by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The response surface methodology (RSM) based on the Box-Behnken design is used to evaluate and optimize the hydrolysis reaction variables. The optimum reaction conditions for the hydrolysis of castor oil by the Fe3O4@CS@CRL heterogeneous catalyst are found to be a water/oil ratio of 1.60: 1, pH of 7.05, reaction temperature of 34 degrees C, and lipase concentration of 3.27%; under these conditions, the hydrolysis conversion of castor oil reached 46.81%. Moreover, the immobilized lipase showed high stability with no appreciable loss in its activity after three consecutive cycles.