Chitosan extracted from Portunus sanguinolentus (three-spot swimming crab) shells: its physico-chemical and biological potentials

Aim: To summarize the extraction, physio-chemical, antibacterial and antioxidant properties of extracted chitosan from the exoskeleton of three-spot swimming crab, Portunus sanguinolentus as compared to commercial chitosan. Methodology: Chitosan biopolymer was extracted through demineralisation, deproteinization and deacetylation. The physicochemical characterization of the extracted chitosan was carried out using Fourier Transforms Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Thermogravimetric analysis (TGA) and Colorimetric analysis. Antibacterial activity using different concentrations of chitosan against Escherichia coll and Aeromonas hydrophila were tested by disc-diffusion method, while antioxidant activity was estimated by 1,1 -diphenyl-2-picrylhydrazyl (DPPH) and H2O2 scavenging assay. Results: Crab chitosan (CC) showed the maximal zone of inhibition (17.00±0.50 and 15.16±0.577 mm), while commercial chitosan (CMC) showed 12.67±0.577 and 14.17±0.288 mm) against E coll and A. hydrophila respectively. The scavenging potential of extracted chitosan ranged from 14 to 17% at different concentrations (0.05 to 0.2 mg ml'1). Crab chitosan efficiency to scavenge 1,1 -diphenyl-2-picrylhydrazyl (DPPH) radicals varied from 7.2 to 12.98% at different concentrations (0.05 to 0.2 mg mf'). Interpretation: Overall, the extracted chitosan exhibited properties to commercial chitosan, suggesting that it could be utilized as a dietary supplement in the fishery sector to protect against bacterial infections. This circular economy approach could significantly benefit sustainable waste management and environmental health.