Review on transesterification of non-edible sources for biodiesel production with a focus on economic aspects, fuel properties and by-product applications

Biodiesel has privileges than conventional diesel fuel because of its low toxicity, renewability, and eco-friendly properties. Biodiesel is produced from various edible and non-edible sources via transesterification process. Non-edible sources such as waste cooking oil (WCO), algal oil, non-edible vegetable oil, and waste animal oil are commonly used to produce biodiesel due to their low cost and no dependency on the food chain. The production process is influenced by several factors such as reaction temperature and time, alcohol to oil molar ratio, and catalyst type and concentration. The analyses of economic aspects of biodiesel production are crucial to reduce the cost of biodiesel production by finding alternatives to available technologies, catalyst, and feedstock. Moreover, the biodiesel production cost is affected by factors such as the type of raw material, by-product selling price, operation and labor cost, the catalyst, and the reaction type. Besides, crude glycerol is a major by-product of biodiesel production with yields ranging between 8% and 10%. Crude glycerol could be used as a beneficial material to produce biopolymers, hydrogen, ethanol, and fuel additive through pyrolysis and gasification processes. Therefore, this review focuses on the recent finding in transesterification of non-edible sources for biodiesel production as well as its economic aspects, fuel properties, and by-products applications. Finally, the economic aspects and process optimization of biodiesel production should be considered as important factors in order to enhance the economic sustainability of biodiesel production.