Bread Waste: Fermentation and Industrial Utilisation Strategies

Abstract Waste bread accounts for a large share of the world's food loss, with output reaching tens of millions of tonnes each year. Its rich starch and nutrient content makes waste bread a promising feedstock for bioconversion routes that turn this residue into biofuels, specialty chemicals, and microbial biomass. At the heart of these processes lie enzymatic and microbial treatments that release fermentable sugars via saccharification, followed by fermentation using yeasts, bacteria, or filamentous fungi. Integrated biorefinery models bring together several conversion stages – for instance, combined bioethanol and organic acid production, anaerobic digestion of leftover residues, and carbon capture – to boost economic viability while limiting environmental impact. Obstacles still exist around logistics, pretreatment efficiency, process integration, and lifecycle sustainability; nevertheless, recent progress shows that circular biorefining of bread waste is capable of delivering climate benefits and commercial-scale value creation together. Information © The Author 2026