Review on utilization of rubber seed oil for biodiesel production: Oil extraction, biodiesel conversion, merits, and challenges

The greater demand for energy has led to a surge in the utilization of fossil fuels, resulting in the rapid depletion of crude oil sources. Regrettably, this trend has engendered a significant negative environmental impact, primarily due to the release of unwanted carbon emissions into the atmosphere. Biodiesel has been considered a suitable substitute for fossil fuels owing to its availability from renewable feedstock, less polluting, sustainable and high biodegradability. However, the production of biodiesel from edible oils is very expensive due to the food versus fuel competition of the oil feedstock. Therefore, non-edible oils such as rubber seed oils have been considered suitable biodiesel feedstock due to their wide availability and abundance in different parts of the world. Rubber plantations are widely cultivated for their latex and the discarded seeds from rubber plantations could be considered as a potential source for biodiesel production. Hence, this review considers the extraction of oil from rubber seeds, the free fatty acid compositions, and physicochemical properties. It investigates biodiesel production from rubber seed oil and explores the variations in its physicochemical properties. The various kinds of catalysts that have been developed for biodiesel production from rubber seed oil were examined; the techno-economic analysis was discussed; the merits and challenges associated with the use of rubber seed oil as a suitable feedstock for biodiesel production were analyzed.