Magnesium-alumina (Mg-Al2O3) composite was synthesized by sol-gel method. The SO42− catalyst supported Mg-Al2O3 was prepared by three different methods such as solution, hydrothermal, and vapor phase. The as-synthesized materials were characterized by different physicochemical techniques. The acid sites of Mg-Al2O3 (10) composite were enhanced by depolymerization of triglyceride (jojoba oil) to produce free FFA. Catalyst prepared by hydrothermal methods exhibits high acid sites of 3.44 mmol g−1 of NH3. Sulfidation of catalysts play a vital role in the catalytic conversion of jojoba oil by methanol activation. SO42−/Mg-Al2O3 (10) catalyst reveals 99% conversion efficiency tested under optimized conditions of jojoba oil to methyl ester (biodiesel). TGA result confirmed the S2/Mg-Al2O3 (10) catalyst is stable upto 800°C and weight loss of 19.2%. The recyclability of the S2/Mg-Al2O3 (10) catalyst reveals reasonably acceptable conversion efficiency after sixth cycle and this catalyst is found to be suitable for the industrial biodiesel production.