Extraction and characterization of chitosan obtained from shells of crab (Callinectes bocourti and Callinectes...

Chitosan is a biopolymer derived from the deacetylation of chitin, which has properties that are highly dependent on the biological source and extraction conditions. The study's aim is to extract and characterize chitin and chitosan from crustacean industrial waste, which is derived from a mixture of two crab species, viz. Callinectes sapidus and Callinectes bocourti. This waste material is not currently used by the seafood industry on the Atlantic coast of Colombia. The reason for using this native mixture lies in the abundance of both species along the region, and the novelty of Callinectes bocourti, which has not been previously studied as a source of chitosan. The extraction is performed under practical chemical conditions to ensure simplicity and scalability. The resulting chitosan is characterized by ATR-FTIR, SEM, XRD, TGA/DSC, and in vitro adhesion assays using Vero cells. The chitosan that is extracted from the mixed species (CS) exhibits a deacetylation degree of 84.1 %, low ash content (0.87 %), and a reduced Crystallinity Index of 30.7 %. The thermal analysis reveals two main mass loss stages, with degradation temperatures of 295.8 °C and 307.9 °C for commercial chitosan (CS-C) and CS, respectively. DSC analysis shows exothermic peaks at 304.6 °C and 311.1 °C for CS-C and CS, respectively. Additionally, the CS shows significantly higher Vero cell adhesion than CS-C. The results suggest that CS meets critical structural and functional criteria for biomedical use, providing a sustainable route for waste valorization. However, biological characterization is limited to preliminary cell adhesion assays. Further, in vitro and in vivo studies are recommended.