Re-use of crustacean shell waste

Scottish langoustines and crabs are highly regarded as some of the best seafood in the world. There are around 30 crab and langoustine processors in Scotland and because we only eat the flesh of these animals, the processors generate approximately 6500 tonnes of shell waste each year. Most of this waste is put into landfill, composted or disposed at sea. However, crustacean shells contain valuable compounds that are relevant to lots of different industries. For example, chitin (in the form of chitosan) can be used as a flocculant to clarify polluted water. It also has uses as a dietary supplement, in cosmetics and in medical devices. Currently, commercial chitin extraction from shells uses harsh chemicals which can destroy other valuable shell components such as protein and pigments.

Heriot-Watt in collaboration with the company Pennotec are therefore seeking to develop a more benign and environmentally friendly process to extract chitin from crustacean shells. This more gentle approach should allow the co-recovery of pigments and protein from the shell which could be sold as a natural colourant feed supplement for salmon production. The increased value of extracts should help make the new approach to chitin extraction from crustacean waste commercially viable as well as having the potential to reduce the environmental impact of aquaculture systems in Scotland.