Biodiesel Production from Waste Cooking Grease: Optimization and Comparative Productivity Assessment

This study evaluated the recovery rate of Fatty Acids Methyl Ester (FAME) using various waste cooking greases from local restaurants. The productivity of biodiesel was analyzed based on the FAME contents and profiles according to the source of greases. Adapting a statistical approach, Response Surface Methodology (RSM), various transesterification based on the ratio of catalyst (KOH) and methanol was evaluated experimentally. Results presented a significant difference in total FAME recovery depending on reaction condition. RSM revealed the optimal blending condition of methanol (59−100 ml) and KOH (2.2−3.2 g) for waste cooking greases of bovine, swine, and poultry, which presented similar FAME characteristics when compared with other biodiesels. Optimal conditions for bovine, swine and poultry made the potential of biodiesel recovery from greases as high as 57.0%, 55.3%, and 53.7%, respectively. Overall, suggested optimized transesterification of waste cooking grease prevents unnecessary resource waste and enables the concept of waste-to-energy. It is also eco-friendly due to reduced pollutant emission and fossil fuel substitution.