As a result of global urbanization and modernization, the use of petroleum (fossil fuel) is on the increase and there are growing concerns among stakeholders in the oil and gas industry over the depletion rate of petroleum reserves and its rising cost. The conversion of readily available sources of biomass to produce different types of biofuels to address the future energy crisis is one of the preferred attractive choices. Biodiesel is generally produced by the transesterification reaction of vegetable oils, waste vegetable oil or animal fats in the presence of a suitable catalyst. The choice of biodiesel as a preferred renewable source of energy was based on its biodegradability, non-toxic, lower emissions, sulphur free, low levels of polycyclic aromatic hydrocarbons (PAHs) and their nitrated compounds. This alternative source of energy is environmentally friendly and could be used in the existing diesel engines with little or no modifications. This will reduce the world's dependence on fossil fuels that are non-renewable with the attendant environmental benefits to mankind. However, the use of these edible vegetable oils will put pressure on the food uses of such oil which will result to fuel-food crisis in the future. This impending crisis can be readily averted by exploring non-edible crops/agricultural waste biomass that can be grown or harnessed domestically and capable of producing oils as valuable raw materials for the emerging industry. A free fatty acid (FFA) lower than 3% is necessary to carry out the base catalysed reaction to end. For biodiesel production, the higher the acid value of the oil, the lesser the conversion efficiency hence the need for esterification process. Papaya seed contains 27.3% to 28.3% protein, 28.2% to 30.7% lipids, and 19.1% to 22.6% crude fibers, it is not economically used. The majority of seeds are produced as residues and discarded as agricultural waste during fruit processing, generating environmental issues. Oil is abundant in papaya seeds (13.9% to 40.0%), which is rich in monounsaturated fatty acids and beneficial phytochemicals as tocopherol, carotene, and phenolics. This provides information on how to reduce pollution and make waste seeds lucrative. As a result, the CPSO is receiving an increasing amount of attention.
Read full abstract