Immobilization of lipase on graphene oxide: A biocatalyst for Esterification of oleic acid

Abstract Graphene Oxide (GO) provides excellent support for lipase enzyme immobilization due to its oxygen-containing functional groups and large surface area. In this work, we synthesized Candida rugosa lipase-immobilized GO and used it as a catalyst for the esterification process of oleic acid for biodiesel production. Different concentrations of (50–200 mg) Candida rugosa lipase enzyme immobilized on GO were used as catalysts. Physicochemical methods like X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and DRS-UV visible spectroscopy were used to describe the catalysts. HR-TEM studies have examined the surface morphology of GO and Candida rugosa lipase-immobilized GO. The catalytic activity was determined by esterifying oleic acid with ethanol to produce ethyl oleate. Gas Chromatography was used to identify the compounds using an internal standard. The various reaction conditions were altered to achieve the highest yield of ethyl oleate by varying the reaction process temperature, reaction duration, different concentrations of Candida rugosa lipase immobilized in GO, and the quantity of catalyst. A maximum oleic acid conversion of 89% was achieved using 150 mg of Candida rugosa lipase-immobilized GO (150 CR/GO). Hence, Candida rugosa lipases immobilized in GO were a good choice for biodiesel production.