InfoSAWIT, MEDAN – A research team from the University of North Sumatra (USU) has discovered a new way to produce sustainable palm biodiesel by utilizing Indigofera zollingeriana leaf waste as a calcium oxide (CaO)-based catalyst. This discovery not only offers a clean energy alternative but also opens up opportunities for a circular economy in Indonesia.
The research findings, published in the 2025 edition of the journal Results in Engineering, were written by Taslim, Silvia Nova, Renita Manurung, Iriany, Vikram Alexander, and Anggara Dwita Burmana. The article, titled "Sustainable production of CaO rich-indigofera (Indigofera zollingeriana) as a heterogeneous catalyst of biodiesel from refined bleached deodorized palm olein using an associated transesterification process," highlights efforts to reduce Indonesia's dependence on fossil fuels by leveraging local resources.
Indonesia, as the world's largest palm oil producer, has great potential for biodiesel development. However, biodiesel production has so far relied on homogeneous chemical catalysts that are difficult to separate from the final product and generate liquid waste. Through this research, the USU team offers a solution using a heterogeneous catalyst from calcined indigofera leaf ash, which produces CaO.
"This approach addresses two issues at once: energy and sustainability. We are not just talking about biodiesel, but also how to utilize cheap, abundant, and environmentally friendly local resources," said Taslim, one of the lead researchers, as quoted by InfoSAWIT from the University of North Sumatra (USU) on Wednesday (9/24/2025).
Laboratory tests showed that the indigofera catalyst effectively converted refined bleached deodorized palm olein (RBDPO) into quality biodiesel that meets international standards. The catalyst can also be used repeatedly without a significant decrease in performance while producing much less waste than conventional catalysts.
Interestingly, indigofera is known as a fast-growing plant that does not compete with food crops and is commonly used as animal feed. Utilizing its leaf waste adds new economic value without disrupting the supply chain. If further developed, the production of this catalyst could potentially involve rural communities in the collection, drying, and processing of the leaves, creating new job opportunities.
While the results are promising, the research team acknowledges there are still challenges, such as the high energy needs of the calcination process and long-term testing for catalyst durability at an industrial scale. However, they are optimistic that this research can be an important foundation for the development of more environmentally friendly renewable energy.
"Biodiesel is often called the energy of the future. But for it to be truly sustainable, its production process must also be eco-friendly. That's what we are trying to prove with indigofera," Taslim said.
This research confirms that clean energy innovation can emerge from simple resources that are often overlooked. By using agricultural waste as a catalyst, Indonesia can become not just a user, but also a producer of knowledge and technology in the global energy transition. (T2)
