Catalytic oxidative depolymerization of lignin into oligomers with multifunctional plant growth regulation in low...

The extensive use of chemicals in modern agriculture has led to severe soil and ecological degradation, necessitating sustainable alternatives. Lignin, as the most abundant renewable aromatic polymer, represents an underutilized bioresource with great potential for agrochemical applications. However, its structural complexity and limited bioavailability have hindered its direct use. In this study, we developed a catalytic oxidative depolymerization strategy employing a CuO/NC catalyst to valorize enzymatic lignin into lignin oxidative oligomers with enhanced bioactivity and multifunctional regulatory effects. The resulting oligomers function as efficient plant growth regulators at low concentrations (1-5 mg/L), significantly promoting early growth in economic crops, enhancing salt stress tolerance, and improving root-to-shoot metal translocation. Mechanistic studies reveal that these effects are mediated through the upregulation of phenylalanine metabolism, tricarboxylic acid cycle, and carbohydrate biosynthesis. This work provides a sustainable and efficient approach for valorizing lignin-rich biorefinery residues into multifunctional, environmentally friendly agrochemicals.