Membrane Processes for Agro-Food Waste Valorization: From Bioactive Recovery to Circular Biorefineries

The agro-food industry generates enormous volumes of processing residues —olive mill wastewater, cheese whey, wine pomace, citrus peels, brewing by-products, and vegetable processing effluents— that remain largely underutilized despite being rich in proteins, polyphenols, pigments, dietary fibers, and other bioactive compounds with well-documented food, nutraceutical, and pharmaceutical value. As regulatory priorities evolve and frameworks such as the EU Farm to Fork Strategy, Horizon Europe’s bioeconomy cluster, and national circular economy action plans gain traction, the case for systematic valorization of these streams has become both scientifically compelling and economically urgent.Recovering functional ingredients from complex agro-food matrices is technically demanding. Conventional thermal and chemical extraction methods frequently degrade heat-sensitive compounds, generate secondary waste streams, and impose high energy costs. Membrane-based processes —including microfiltration, ultrafiltration, nanofiltration, reverse osmosis, forward osmosis, and membrane distillation— offer a cleaner and more selective alternative. Operating under mild conditions that preserve bioactivity, these technologies enable the fractionation and concentration of target molecules directly from raw processing streams, with minimal thermal stress and reduced solvent use. Advances in novel membrane materials, including graphene oxide composites, metal-organic framework (MOF)-based membranes, and bio-inspired fouling-resistant surfaces, are further expanding what is achievable in terms of selectivity, throughput, and operational lifespan.Beyond individual separation steps, membrane systems are increasingly positioned as the backbone of circular biorefinery frameworks, where multiple value streams —bioactive ingredients, process water, and energy-relevant fractions— are recovered from a single feedstock in a cascaded, resource-efficient workflow. This integrative approach, combining membrane unit operations with fermentation, enzymatic treatment, or adsorption, creates genuine pathways from agro-food waste to high-value products at pilot and industrial scale.This Research Topic welcomes original research articles, systematic reviews, methods papers, and techno-economic or life cycle analyses from researchers and practitioners working across food science, chemical and biochemical engineering, environmental science, and industrial biotechnology. We are particularly interested in contributions that bridge the laboratory-to-scale-up gap, critically examine process economics, or model the environmental performance of integrated membrane-biorefinery systems.Key topics and questions to be addressed include:—How can membrane technologies enhance the recovery of bioactive compounds from agroindustrial residues?—What are the latest advances in emerging membrane processes (e.g., forward osmosis, membrane distillation) for such applications?—How can membrane systems be integrated into biorefinery concepts?—What are the main challenges related to fouling and process optimization?—What is the environmental and economic performance of these processes (e.g., LCA, techno-economic analysis)?—How can circular economy principles be effectively implemented in membrane-based separations?By transforming agro-food residues into streams of functional ingredients, membrane processes contribute to circular bioeconomy principles and supports SDG 12 (Responsible Consumption and Production) as a primary objective, while contributing to SDGs 2, 6, 7, 9, and 13 through enhanced resource efficiency, pollution reduction, and sustainable industrial innovation. We invite the global research community to contribute to this field at a critical moment in its development. Topic editors: Katia Rezzadori, Penha, Frederico Marques, Isaac Owusu-Agyeman Source: https://www.frontiersin.org/research-topics/81004/membrane-processes-for-agro-food-waste-valorization-from-bioactive-recovery-to-circular-biorefineries