Utilization of Macadamia Nut Oil as a Feedstock for a Sustainable Biodiesel Production

Although fossil fuel continues to play a dominant role in global energy systems unfortunately their life span is threatened as the fossil reserves are running out. Except for the fact that they are readily available, tried, and tested, unfortunately, they bring about a negative environmental and climate impact. When fossil fuels are burned, they produce both carbon dioxide and carbon monoxide which is the largest driver of global climate change and air pollution. This has caused a need to explore and transition to a cleaner and renewable energy resource like biofuel. Biofuel is a combination of long-chain fatty acids of mono-alkyl esters achieved by the esterification and transesterification of triglycerides that can either be animal fats or vegetable oil with methanol and ethanol. Biodiesel provides several positive benefits by helping to decrease the country’s dependence on the importation of crude oils, it also reduces greenhouse gas emissions and advances the lubricating property. Biodiesel is produced and deployed globally with China being the highest producer of biofuel in the world, with nearly 29.8 gigawatts as of 2021. It is followed by Brazil which is ranked second, with a biofuel capacity of 16.3 gigawatts. The selection of a feedstock in biofuel production has a noticeable impact as it determines if a biofuel will be formed or not from the transesterification process performed. The fatty acid/triglyceride content especially the Mono - Unsaturated Fatty Acids (MUFA’s) are of interest. The higher the MUFA’s, the higher the possibility of a successful transesterification hence biofuel being the by-product/formation with less catalyst and alcohol used. Feedstocks with over 40% fatty acids, especially the MUFA’s are favorable for biodiesel formation. Almost 80% of Macadamia’s fatty acids (MFAs) are palmitoleic acids (C16:1; ~20%) and Monounsaturated, mostly oleic (C18:1; ~60%).