Abstract Fe 3 O 4/ZnO core/shell magnetic nanoparticles in 1: 1 and 1: 2 molar ratios were prepared and characterized by using X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis, FT-IR spectra, and flame atomic absorption spectrophotometry. Thermomyces lanuginosa lipase (TLL) was then covalently immobilized on the surface of both supports. An immobilization efficiency and yield of 94±2.5% and 86 ...