A Comparative Review of Vegetative and Animal-Based Biodiesel: Feedstock Selection, Synthesis Method, Characterization Technique, and Economic Perspective

The urgent need for sustainable energy solutions has intensified research into biodiesel as a viable alternative to fossil fuels. With rising concerns over greenhouse gas emissions and energy security, biodiesel derived from renewable feedstocks presents a promising pathway toward low-carbon development. However, the selection of optimal feedstocks and efficient extraction techniques remains critical to enhancing its economic viability and environmental sustainability. This review explores biodiesel production from both vegetative and animal-based feedstocks, focusing on their potential as renewable energy sources. Key extraction techniques, including mechanical, solvent, and advanced methods are critically examined for their effectiveness in lipid extraction. The review further evaluates five biodiesel production methods: transesterification, supercritical transesterification, pyrolysis, blending, and micro-emulsification, with a particular focus on transesterification due to its efficiency and favorable outcomes. The study emphasizes the physicochemical properties of biodiesel, ensuring compliance with ASTM 6751 and EN 14214 standards. By providing a comprehensive assessment of feedstock availability, process efficiency, and sustainability considerations, this review contributes to advancing the role of biodiesel in the transition toward climate-friendly energy solutions. The findings reinforce the role of biodiesel in mitigating climate change by reducing dependency on fossil fuels and promoting circular bioeconomy practices.