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

Abstract

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 °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.Practical Applications: RSM is found to be a useful technique for optimizing hydrolysis of castor oil. The high conversion of the hydrolysis of castor oil indicates that the Fe3O4@CS@CRL have potential to be used in preparing ricinoleic acid from castor oil. Ricinoleic acid have the potential to be used in printing ink as a pigment and dye disperser, plasticizers, surfactants, lubricants, and other valuable products.Ricinoleic acid can be used in pigment and dye disperser in printing ink, sebacic acid, azelaic acid, heptaldehyde, plasticizers, surfactants, lubricants, and other valuable products. Hydrolysis of castor oil catalyzed by Candida rugosa lipase (CRL) immobilized on glutaraldehyde‐activated magnetic Fe3O4@chitosan is investigated. The response surface methodology (RSM) based on the Box–Behnken design is used to evaluate and optimize the hydrolysis reaction variables. Fe3O4@CS@CRL can be easily separated from the suspension using an external strong magnet. Fe3O4@CS@CRL have potential to be used in preparing ricinoleic acid from castor oil.