The aim of this work was to use a unique technique to maximize the efficiency and cost-effectiveness of biodiesel synthesis utilizing Aloe vera oil. Moreover, in order to facilitate the magnetic separation from the resultant mixture, lipase was immobilized on a magnetic nanocomposite consisting of polyaniline (PANI) and Fe3O4. Utilizing XRD, SEM, TGA and FTIR spectroscopy, the nanocomposite was thoroughly characterized. The results indicated that the immobilized lipase exhibited enhanced thermal stability and a modified optimum pH compared to its free form. Using immobilized lipase also significantly improved the biodiesel conversion yield from 27% with free enzyme to 60%. Remarkably, after five cycles of reutilization in the production of biodiesel, the immobilized lipase retained 90% activity. The catalytic effectiveness of lipase during biodiesel synthesis was significantly enhanced and its resistance to heat and pH fluctuations was strengthened by this novel immobilization approach. Beyond its potential usage in biodiesel production, the PANI-Fe3O4 magnetic nanocomposite also demonstrated photocatalytic removal and degradation of methyl violet dye from aqueous solution.