Isolation and characterization of chitosan from Ugandan edible mushrooms, Nile perch scales and banana weevils for biomedical applications.

Background: Of recent, immense attention has been given to chitosan in the biomedical field due to its valuable biochemical and physiological properties such as biodegradability, biocompatibility, non-immunogenicity, reactivity, solubility and non-toxicity. For instance, chitosan has exhibited distinguished bioactivity not limited to only antimicrobial activity but also promotion of wound healing and immune system augmentation in model animals. Therefore, chitosan has attracted application as a nano drug targeted delivery system. Traditionally, the chief source of chitosan is chitin from crab and shrimp shells obtained as waste products in the seafood industry. Chitin is also an important component of fish scales, insects and fungal cell walls, therefore, Uganda’s edible mushrooms, Nile perch scales and banana weevils can be used as alternative sources of chitin and obviously chitosan. Thus, the aim of this study was to isolate and characterize chitosan from locally available material for potential use in the biomedical field. Methods: Chitin was extracted from banana weevils, Nile perch scales and mushrooms powder by demineralization with 1.0M HCl solution, then deproteinization with 1.0M NaOH. Chitosan was prepared by treating chitin with 50% NaOH at 100°C for 8 hrs. Chitosan ash and moisture contents were determined gravimetrically while solubility was computed as percentage dry weight of suspended chitosan. FTIR was used to determine the DD while XRD was used to estimate the crystallinity of chitosan. Results: Ash and moisture contents ranged from 3.5 to 15% and 3.5 to 6.4% respectively while solubility level varied from 57 to 68%. FTIR spectra reveal high degree of similarity between locally isolated chitosan and commercial chitosan with DD ranging from 77.8 to 79.1%. X-Ray Diffraction (XRD) patterns exhibited peaks at 2θ values of 19.5° for both chitosan extracted from Mushrooms and banana weevils while chitosan from Nile perch scales registered 3 peaks at 2θ angles of 12.3°, 20.1° and 21.3° comparable to the established commercial chitosan (Sigma Aldrich) XRD pattern. Conclusion: Ash content, moisture content, DD, FTIR spectra and XRD pattern revealed that chitosan isolated from locally available materials has physicochemical properties comparable to conventional chitosan and therefore it can be used in the biomedical field.