A sustainable upcycling system integrating adsorption and catalysis was developed using Maillard reaction-induced fish gelatin/polylysine (FG/PL) nanofibers. To improve the structural stability and functional properties of the FG/PL nanofibers, ribose was introduced to induce Maillard reaction–mediated crosslinking. The incorporation of PL into FG matrix not only enhanced the cationic character of the nanofibers but also enhanced Maillard reaction-induced crosslinking. The optimized FG/PL30_2h nanofiber achieved rapid adsorption equilibrium within 60 min and exhibited a maximum adsorption capacity of 88.91 mg g−1, well-fitted by the Langmuir model. The Pd-loaded nanofiber (Pd/PL30) efficiently catalyzed the reduction of 4-nitrophenol within 5 min, maintaining over 90% activity after six cycles. This biopolymer-based strategy provides a green and recyclable route for noble metal recovery and catalytic upcycling, demonstrating the potential of Maillard crosslinking as a sustainable platform for environmental and energy applications.