Lignin is the most abundant naturally occurring aromatic polymer and a primary component of lignocellulosic biomass. Although large quantities of lignin are produced annually as a by-product of the pulp and paper manufacturing and biorefining processes, more than 95% of it remains under-utilized. These lignins are mainly utilized for combustion to produce energy or in low-value applications. However, formulating strategies for their higher-value applications still poses a challenge. In recent years, the emergence of the “lignin-first” biomass refining strategy, along with advances in novel catalysts, solvent systems, and biotechnology and enzymatic processing, has enabled significant progress in lignin depolymerization and its high-value utilization. In particular, metal-loaded catalysts have been demonstrated to effectively facilitate the cleavage of C–C and C–O linkages between phenylpropane units in lignin, thereby enabling their conversion into valuable aromatic compounds. Moreover, biotechnology and enzyme-based approaches offer promising routes for selective lignin breakdown under mild and environmentally benign conditions. Meanwhile, the range of applications for depolymerisation products continues to grow, extending from traditional agricultural materials and polymer fillers to high-value biomedical materials, energy storage materials and environmentally friendly functional materials.

This research topic will focus on the latest technologies for depolymerizing lignin and its use in high-value applications. It will cover the entire innovation chain, from fundamental research to engineering implementation. Through this research topic, we aim to advance fundamental theoretical innovations and technological breakthroughs in the field of preferential lignin depolymerization strategies and expand the application boundaries of lignin derivatives in new materials, energy sources, pharmaceuticals and other fields. Moreover, it is advantageous for encouraging interdisciplinary cooperation and speeding up the commercialization of laboratory research results. Finally, we expect to provide technological support for advancing the global circular carbon economy and fostering the growth of bio-based industries.

We welcome original research, reviews, mini-reviews, and perspectives on the technological exploration and high-value applications of lignin depolymerization. Submissions may address, but are not limited to, the following areas:
1. Design and optimization of novel lignin catalytic systems, including enzymatic and biocatalytic routes, and in depth studies on depolymerisation mechanisms.
2. The “lignin-first” biomass refining strategy and its implementation in lignocellulosic biorefinery and industrial biotechnology processes.
3. Development of green solvent systems and process intensification technologies for efficient lignin depolymerisation in bio-based production.
4. Applications of lignin depolymerisation products and derivatives in bio-based functional materials and polymer processing.
5. Integrated systems for lignin depolymerisation and subsequent microbial, enzymatic and/or chemical conversion to value-added products.
6. The influence of pretreatment methods and structural regulation on lignin depolymerisation behavior and compatibility with downstream bioprocesses.
7. Innovative applications of computational chemistry and artificial intelligence to guide catalyst design, enzyme engineering, bioprocess modelling, and product development in lignin depolymerisation.
The following types of research are not within the scope of this Research Topic:
• Studies focused solely on material synthesis and characterization without demonstrating a specific application.
• Studies reporting only computational results without any experimental validation.

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Lignin Depolymerization: Technological Exploration and High-Value Applications