Magnetic nanoparticles (Fe3O4/Ag NPs) covered with tartaric acid (TA) have been synthesized through an "eco-friendly” approach and used for direct physical immobilization of lipase from Thermomyces lanuginous (TLL). The immobilized lipase was tested for the production of biodiesel from grape seeds oil, and in a solvent-free system. The maximum yield to biodiesel was about 94%, at the methanol/oil molar ratio of 1:6. In the same operating conditions free lipase exhibited, after 24 h, a maximum yield of 77%. Moreover, the FAME content in biodiesel was ~96.54% in accordance with European Standards.
