The study focuses on a sustainable biorefinery approach to transform food waste into polyhydroxyalkanoates (PHA) and biogas. Ultrasonic assisted alkaline pretreatment (UAP) was utilized to enhance the biodegradability of food waste, achieving a greater solubilization efficiency than ultrasonic pretreatment (UP). The pretreated food waste hydrolyzate was used for PHA production, while the residues were utilized for biogas recovery. The results showed that 60% food waste hydrolyzate was optimal for enhanced biopolymer production, with a positive net profit of 6.81 USD/Ton. The study highlights the potential of food waste biorefinery in generating bioenergy, valuable chemicals, and promoting a circular bioeconomy by achieving zero waste generation and sustainable recovery. Integrating different approaches for bioenergy and valuable product generation from food waste is essential for sustainable development.