Sustainable Biodiesel Production From High‐ <scp>FFA</scp> Chicken Waste Oil: <scp>RSM</scp> ‐Based Optimization of Esterification and Transesterification Processes

ABSTRACT Growing concerns over environmental impact and limited fossil fuel reserves have led to the urgent need for sustainable and renewable energy alternatives, such as biodiesel, to decrease pollution and ensure long‐term energy security. This study focused on utilizing chicken waste oil, a cost‐effective by‐product of the food industry with high free fatty acid (FFA) content (&gt; 25%), to produce biodiesel that aids waste management. A two‐step process involving acid esterification followed by base transesterification was employed. Response surface methodology (RSM) was applied to optimize key process parameters with the aim of improving efficiency and reducing reactant usage. The esterification process reduced the acid value to 1.32 mg KOH g −1 , making it optimum for the transesterification process. A maximum biodiesel yield of 98.9% was achieved with reduced reaction time and lower reactant consumption compared to conventional processes, enhancing the process's environmental sustainability and cost‐effectiveness. The produced biodiesel exhibited favorable fuel properties, including density (at 20°C), viscosity, and calorific value, satisfying ASTM standards. Chicken waste oil, despite its high FFA content, demonstrates strong potential as a biodiesel feedstock, contributing to reduced CO 2 emissions and supporting climate change mitigation.