Sustainable Industrial Applications of Chitosan and Chitosan-Based Nanomaterials: Advances and Challenges

Chitosan (CS), a biofunctional biopolymer derived from chitin, has emerged as a versatile platform for advancing sustainable industrial technologies. Its intrinsic biodegradability, biocompatibility, and structural tunability support applications across textiles, wastewater treatment, biofuels, and energy storage. Recent advances in chemical modification, nanostructuring, and hybrid material engineering have broadened its functionality, yielding enhanced solubility, stability, antimicrobial activity, and stimulus-responsiveness. This review examines state-of-the-art modification strategies and industrial applications of CS and CS-based nanomaterials, while highlighting the role of digital and cleaner production technologies in shaping their future. Integrating CS with artificial intelligence (AI), additive manufacturing, and bioinspired design further reinforces its potential in next-generation green materials science. However, challenges remain in scaling up cost-effective production, ensuring consistency, and navigating regulatory frameworks. Finally, it discusses key limitations and emerging opportunities for CS as an enabling material in the circular and bio-based economy.