Green and Sustainable Approaches for Chitosan Extraction: An Ecological Perspective on Marine Waste Management

Chitin, a valuable component, is present in crustacean shells and other sources and can be extracted via chemical and biological methods, and is subsequently deacetylated to produce chitosan, which possesses numerous applications in various fields. Though these techniques are efficient, owing to the drawbacks of ionic liquids and green solvent-mediated chitin extraction methods, they have been developed in recent years. Chitin extraction was focused on multiple strategies owing to its applicability. In this study, as an alternative approach, one-step extraction of chitosan is achieved, eliminating the deacetylation step. Using phytoextract-mediated extraction, chitosan was directly extracted without an intermediate chitin product. The Annonaceae family, specifically, Annona muricata (Graviola), rich in acetogenins, was utilized in this study to directly extract chitosan from its source. Chitin extraction was efficiently carried out from various sources such as shrimp, prawn, and freshwater prawns. Chitosan's presence was determined by qualitative analysis, and the DNSA assay was used to quantify its amount. Similarly, FT-IR, XRD, and TGA/DTA studies were employed for chitosan characterization. The experimental results indicate the chitosan's presence, which aids in the possible recovery of chitosan directly from the sources using graviola leaf powder. This research indicates the potential recovery of chitosan from shells utilizing an acetogenin compound in the graviola leaves.