Particularly, supercritical carbon dioxide (scCO2) is used for the extraction oils. This method can be tried for the extraction of lipid from food wastes. Lipid extracted using scCO2 is not contaminated with organic solvents unlike the conventional extraction processes. Moreover, scCO2 extraction process can be optimized by adjusting pressure and temperature [44]. Thus, lipid obtained is clean and can be directly used for biodiesel production. Different lipid extraction processes are summarized in