Sustainability through lignin valorization: recent innovations and applications driving industrial transformation.

Lignin, the second most abundant natural polymer, is emerging as a strategic feedstock for advancing a sustainable and circular bioeconomy. Traditionally underutilized byproduct of lignocellulosic biomass processing, lignin is now central to the development of bio-based chemicals, advanced polymers, and renewable fuels. This review explores recent progress in lignin valorization, focusing on emerging strategies in chemical, thermophysical, and biological depolymerization. Innovations in catalytic conversion, ionic liquid-assisted processing, and biocatalytic approaches are enabling the selective transformation of lignin into high-value products, offering viable alternatives to petroleum-derived inputs. Emerging lignin-based technologies are being adopted across key industries such as packaging, textiles, automotive, construction, and energy, enabling the development of eco-friendly and high-value product solutions. Despite its significant potential, lignin valorization is constrained by challenges including structural complexity, inefficient processing, and scalability limitations. Addressing these issues requires integrated strategies that combine technological innovation, interdisciplinary collaboration, industrial integration, and supportive policy frameworks. Through a critical assessment of the opportunities and limitations in lignin valorization and technology development, this study establishes lignin as a strategic component of next-generation biorefinery systems, advancing green material innovation and enabling resource-efficient, low-emission production in alignment with global sustainability objectives and future industrial research.