2. Preparation, properties and main applications of chitosan

In a global context of waste volume reduction, the reuse of manufacturing co-products or waste themselves is now a priority in terms of sustainable development. The world market for seafood products, and in particular crustaceans (shrimps, crabs, lobsters, etc.), produces several million tonnes per year, half of which is potentially recoverable waste. Shells essentially contain calcium carbonate (which can also be recycled) and a natural polymer called "chitin", which, after extraction, can be chemically modified to produce chitosan, its main derivative. Along with cellulose, chitin is one of the world's most abundant natural polymers.