CIRCULAR BIOECONOMY APPROACHES FOR AGRICULTURAL AND FOOD PROCESSING WASTES: TECHNOLOGIES, BUSINESS MODELS AND SUSTAINABILITY ASSESSMENT

Abstract

One of the most abundant renewable feedstocks that can be used in a circular bioeconomy is agricultural and food processing wastes. These consist of crop residues, manure, fruit and vegetable by-products, dairy and brewery residues, slaughterhouse wastes, spent grains, oilseed cakes and mixed post-consumer food waste. These streams are often dumped, burned, landfilled or discharged into wastewater systems in a linear agri-food system, resulting in economic losses, public-health risks, odours, nutrient pollution and greenhouse-gas emissions. A circular bioeconomy redefines these materials as biological resources that can be prevented, recovered, cascaded, and converted to food, feed, organic fertilizers, soil amendments, bioenergy, biomaterials, platform chemicals and functional ingredients. This review aims to compile authoritative, peer-reviewed literature and institutional reports up to July 2026, focusing on technologies, business models and sustainability assessment approaches. Composting, anaerobic digestion, production of pyrolysis and biochar, gasification, hydrothermal processing, fermentation, enzymatic conversion, insect bioconversion, extraction of bioactive compounds and integrated biorefineries are key valorization technologies. The review also explores business models for resource recovery, cooperative ownership, industrial symbiosis, product-service systems, digital platforms, carbon and nutrient markets and cascading value chains. The concept of sustainability assessment is introduced via the concepts of life-cycle assessment, techno-economic analysis, life-cycle costing, social life-cycle assessment, material flow analysis, circularity metrics and multi-criteria decision analysis. The results indicate a reduction of about 1 t CO2e per tonne of food waste recycled, compared to landfill disposal, due to circular management of food waste, but this depends significantly on the quality of the feedstock, the design of the process, energy substitution, transport distances, digestate or compost application, market demand and policy incentives. Progress will need to be made using integrated biorefineries, harmonised assessment methods, safe use standards for recovered products, digital traceability, and inclusive financing and policies that focus on prevention rather than recycling. Circular bioeconomy strategies can help to decrease environmental impacts and generate new economic opportunities, but they need to be developed as a system that is balanced between ecological limits, social acceptance and economic viability.