Green chemistry strategies in pulping and biomass valorization: toward a circular bioeconomy.

The transition toward a circular bioeconomy demands innovative, sustainable, and efficient technologies for biomass valorization and pulping. Green chemistry strategies, particularly organosolvent pulping pretreatment, are emerging as pivotal solutions to unlock the full potential of lignocellulosic feedstocks. Organosolvent processes employ environmentally benign solvents to selectively fractionate biomass components, enabling the recovery of high-purity cellulose, hemicelluloses, and lignin with minimal environmental footprint. These technologies advance the principles of green chemistry by minimizing hazardous reagents, reducing energy consumption, and promoting waste valorization. Recent developments demonstrate their capacity not only to improve pulping efficiency but also to produce value-added chemicals, biomaterials, and biofuels, thereby closing resource loops and reducing reliance on fossil-based systems. This review uniquely integrates advances in organosolvent pulping pretreatment within the framework of green chemistry and circular bioeconomy. This work systematically compares multiple green solvent systems including ionic liquids, deep eutectic solvents, and bio-derived organosolvent methods alongside catalytic, biocatalytic, and process intensification techniques. It also synthesizes recent industrial case studies, bridging the gap between laboratory research and pilot-to-commercial scale deployment. By highlighting the synergistic role of these technologies in achieving high-purity biomass fractionation with minimal environmental footprint, the review provides actionable insights for researchers, policymakers, and industry stakeholders aiming to accelerate the transition to a regenerative, circular bioeconomy.