▎ 摘　　要

This research used titanium oxide-coated magnetic Fe3O4 nanoparticles doped graphene oxide (MTiGO) and modified with Candida antarctica Lipase B (CALB) enzyme. The MTiGO@CALB nanocomposite is a novel biocatalyst for transesterifying triglycerides to fatty acid methyl esters (FAMEs) from waste cooking oil. tThe physicochemical characteristics of the proposed biocatalyst were determined via FTIR, VSM, XRD, SEM, and EDS techniques. The maximum immobilization efficiencies and activity recovery of immobilized enzymes were obtained at 89% and 75% in the following operating condition: lipase concentration of 2.0 mg/mL, pH of 7.0, immobilization temperature of 35 degrees C, and immobilization time of 4 h. Various effective parameters on biodiesel were stated, and according to the revealed data, the maximum yield of biodiesel via the transesterification process was achieved at 92%, at a reaction temperature of 45 degrees C, catalyst quantity of 4 wt%, aa reaction duration of 40 h, and methanol to molar oil ratio of 5:1 These findings indicated that the provided bio-nanocomposite has a high potential for producing biodiesel as an efficient heterogeneous biocatalyst.