Biodiesel has become an attractive renewable fuel due to carbon footprint reduction. Greenhouse gas footprint is minimised when the locally available renewable feedstock is utilised for cleaner biodiesel production. This biodiesel has similar characteristics of diesel oil which allows its use in compression motors without extensive engine modifications. One of the greenest choices to address the ever growing demand for cleaner energy is renewable biomass power. Contemporary development and work have been aimed at transforming these bio-based resources into practical gas and liquid fuels that comply with the current petro-based chemical production infrastructure. Biodiesel is a prospective alternative to petroleum fuels due to its clean, renewable and ecologically beneficial characteristics. The transesterification cycle is applied to the processing of cleaner biodiesel manufacturing. Comprehensive research is underway to develop more effective biodiesel processing processes. The different new technologies are both solid catalysts and supercritical processes that are not catalytic. A review of the various methods used for the successful synthesis of biodiesel includes the homogeneous, heterogeneous and enzyme catalyst, microwave and ultrasonic synthesis followed by the supercritical synthesis of biodiesel. The chemical reactions of biodiesel, i.e. transesterification, esterification and interesterification have been presented by this paper and the merits and limitations of these chemical reactions for biodiesel discussed.