Transesterification of Crude Rubber Oil Catalyzed by Lipase Extract Powder of Germinated Rubber Kernels for Biodiesel Production

Lipases are essential in many industrial processes. Although microbial lipases are widely used, plant lipases remain more accessible and abundant, particularly in germinated kernels. This study aims to evaluate the catalytic potential of lipase extract powder of germinated rubber kernels in transesterification reaction. Germinated rubber kernels, lipase extract powder of germinated rubber kernels, and crude oils of palm (PKO), Jatropha curcas (JCO), and rubber (RSO) were characterized. The presence of lipase in the plant extract powder was evidenced by FT-IR and SEM-EDX analyses and hydrolysis reaction. Biodiesel was produced from crude rubber oil. The results showed that germinated rubber kernels have high moisture (33.48%), protein (15.75%), and fat (50.11%) contents. The optimum hydrolytic activities of lipase on PKO, JCO, and RSO were 25.67 U/mL, 26.67 U/mL, and 31 U/mL, respectively, at pH 5. Lipase extract concentration, temperature, and storage time influenced the lipase hydrolytic activity. The optimum biodiesel yield (29.63%) was obtained at 30 °C. The addition of co-solvents (water and n-hexane) to the reaction mixture increased yields from 20.47% (without co-solvent) to 31.06% and 21.85%, respectively. These insights show that germinated rubber seeds are rich in oil and contain lipase with good hydrolytic and catalytic activity.