Facile Synthesis, Characterisation, and Catalytic Application of Lipase Immobilized Nickel Oxide Nanoparticles for Biodiesel Production

The growing global demand for clean and sustainable energy has prompted researchers to focus on producing biodiesel using enzymes. In this study, nickel oxide (NiO) nanoparticles were prepared using a sol-gel method and modified to attach lipase enzymes. The resulting nanobiocatalyst was analysed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) to investigate its size, shape, and enzyme attachment. Lipase from Candida albicans was bonded to the NiO particles through covalent linking. This enzyme-nanoparticle system was tested for its ability to convert waste cooking oil into biodiesel. Reaction settings were optimised to achieve the best yield, and the catalyst's ability to be reused was also investigated. Under ideal conditions, the process yielded 88% biodiesel and retained more than 75 % activity even after five uses. These results demonstrate that lipase-bound NiO nanoparticles can serve as a highly effective and reusable catalyst for the production of green biodiesel.