From Blue Bioeconomy toward Circular Economy through High-Sensitivity Analytical Research on Waste Blue Crab Shells

Unlike calcite from geological origin, biogenic calcite from marine organisms have gained an increasing interest in the field of advanced materials due to their hierarchical three-dimensional (3D) nanostructure populated with a gradually distributed organic fraction and due to their porosity. Within the blue bioeconomy context, certain seafood species featuring residual biomineral mass ranging from 80 to 95% of the fresh body weight (bivalves, crustaceans, etc.) could be turned into added-value byproducts, provided that the ultrastructure and nanomorphology are preserved as in intact, native materials. Little is known about species-specific nanomorphology and its subtle chemistry when crab shells are exposed to thermal or mechanical stress for any potential waste industrial processing. We probed here the morphology and chemistry preservation in biogenic CaCO₃ from claw shells of two common crustacean species, Callinectes sapidus and Carcinus aestuarii. We found that mechanical powdering results in their carotenoid preservation in micro- and nanosized porous particles with size distributions characteristic for each original color and that their Bouligand-type (twisted plywood) 3D nanomorphology is preserved during thermal treatment. The results suggest that such a waste biomaterial is suitable for potential industrial design steps toward added-value byproducts following the principles of circular economy for a sustainable society.