Microbial biorefinery of food processing residues advances ecosystem services and sustainable waste management

Food‑processing industries generate large volumes of organic by‑products are frequently underutilized, leading to avoidable environmental burdens when disposed. Microbial biorefineries offer a route to convert these heterogeneous residues into biofuels and high‑value chemicals/materials under mild conditions, supporting circular‑bioeconomy objectives. This review synthesizes recent advances in microbial valorization of food‑processing residues by explicitly linking feedstock physicochemical attributes such as moisture content and spoilage risk, structural recalcitrance, C/N balance, ash/mineral fraction, and inhibitory compounds, to pretreatment needs and bioreactor choice and to culture strategies. We discuss major product portfolios—including ethanol, biogas, organic acids, polyols, polyhydroxyalkanoates, biosurfactants, enzymes, and biosorbents—and highlight representative performance metrics and scale‑up considerations. To facilitate cross‑comparison, we compile indicative residue generation volumes and summarize key feedstock attributes relevant to microbial accessibility and process selection, and we benchmark sustainability evidence from techno‑economic and life‑cycle studies using reported metrics where available. Finally, we identify major bottlenecks such as feedstock conditioning, contamination control, downstream separation, and regulatory/market constraints, and outline opportunities for integrated and hybrid valorization schemes that improve carbon efficiency and ecosystem‑service outcomes. Overall, the review provides a decision‑oriented framework for selecting microbial routes aligned with feedstock properties, product targets, and sustainability goals.