Integrated Net-Zero Food Waste Bioconversion into Three High-Value Green Products

Food waste (FW) upcycling is constrained by fragmented approaches that target single products, rely on refined substrates, and lack operational flexibility, limiting scalability. A key gap is the development of integrated, multiproduct FW bioprocesses that are cost-effective and robust to real-world storage conditions. This study reports a unified FW upcycling platform that simultaneously produces polyhydroxybutyrate (PHB), organic fertilizer, and biofertilizer. The novelty lies in integrating multiproduct valorization to upcycle everything from FW, along with storage resilience and direct use of FW-derived intermediates as fermentation feedstocks. FW can be stored for up to four weeks without loss of bioconversion efficiency, addressing a critical barrier to industrial implementation, while 16S rRNA sequencing reveals microbial stability underlying process robustness. FW-derived lactic acid is directly used as the sole carbon source for fed-batch cultivation of Cupriavidus necator, achieving ∼95% PHB content without costly sugars. Agronomic analyses show that FW-derived fertilizers significantly enhance vegetable growth, with chlorophyll content increasing by 71.6% and 144% in organic fertilizer and biofertilizer treatments, respectively, compared to controls. This work establishes a scalable, storage-resilient, multiproduct FW valorization strategy for circular bioeconomy applications.