ABSTRACT
Chitin can be extracted from three sources: crustaceans, insects, and micro-organisms. The primary commercial sources of chitin are shells from crustaceans, such as shrimp, crabs, lobsters, and krill, that are supplied in large quantities by the shellfish processing industry. The chitin extraction from crustaceans, insects, and micro-organisms requires several steps to demineralize, deproteinize, and decolorize. In conventional industrial processing, the chemical extraction of chitin includes an acid treatment to dissolve the calcium carbonate followed by an alkaline solution to dissolve proteins. A decolorization step is often added to remove pigments to obtain pure colorless chitin. These treatments must be adapted based on the chitin source, taking into account the differences in the original material’s ultrastructure, to produce high-quality chitin and chitosans. Chitin is infusible and sparingly soluble during its transformation. The most common biological methods for chitin extraction are to use proteolytic enzymes to digest the proteins or a micro-organism fermentation process, which allows the digestion of both proteins and minerals.
