Valorization of waste biomass in the circular bioeconomy: advances in pretreatment and catalytic conversion technologies in modern biorefineries.

In the context of global energy transition and carbon neutrality goals, converting lignocellulosic biomass into high-value products is essential for a circular bioeconomy. This review systematically explores technological advancements in modern biorefineries, from feedstock deconstruction to precise valorization. Pretreatment strategies-physical, chemical, and integrated pretreatment strategies-effectively overcome lignocellulose recalcitrance, achieving high-purity fractionation of cellulose, hemicellulose, and lignin. Advanced conversion technologies, including electrocatalysis, photocatalysis, biological funneling, and bio-photoelectrochemical hybrid systems, offer superior selectivity, atom economy, and energy efficiency in biomass upgrading. Addressing economic and stability challenges in scale-up, the integration of artificial intelligence and digital twins promises intelligent, carbon-neutral biorefinery systems. This review provides theoretical guidance and technical roadmaps for closed-loop resource utilization and sustainable development.