<b>Valorization of Shrimp Shell Waste into Functional Chitosan: Recent Advances, Analytical Challenges, and Future Perspectives</b>

Abstract

The increasing accumulation of shrimp shell waste from seafood processing presents both an environmental challenge and an opportunity for sustainable biomass valorization within the circular bioeconomy. Chitosan, a biodegradable and biocompatible polysaccharide obtained through chitin deacetylation, has emerged as a versatile biomaterial with broad applications in biomedicine, agriculture, environmental remediation, food packaging, and advanced functional materials. This review critically evaluates recent advances in the production of chitosan from shrimp shell waste, emphasizing extraction technologies, quality determinants, structural characterization, and analytical evaluation. Conventional chemical extraction is critically compared with emerging green approaches, including microwave-, ultrasonic-, autoclave-, enzymatic-, fermentation-, and deep eutectic solvent-assisted processes, highlighting their effects on yield, degree of deacetylation, molecular weight, scalability, and environmental sustainability. Current characterization and analytical methods are comparatively assessed, with particular emphasis on the complementary role of 3,5-dinitrosalicylic acid (DNSA)-based assays for reducing-end quantification during chitosan depolymerization. The review further discusses advances in functionalized chitosan derivatives, nanocomposites, industrial translation, and sustainable production strategies while identifying standardization of extraction and analytical protocols as a critical requirement for improving reproducibility and facilitating commercial-scale production. Collectively, this review provides an integrated perspective on current progress, remaining challenges, and future research priorities for developing high-quality chitosan from shrimp shell waste.