08. Apr 2026
Biobased films and coatings made from chitin-containing waste materials
The processing of crustaceans from the fishing industry, the production of insect protein, and mushroom cultivation generate large quantities of chitin-containing waste.
The Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB has established a process chain for chitin processing to create added value from these waste streams. These technologies enable the production of high-purity chitosan, which can be used, among other things, for sustainable coatings. Transparent films made from chitosan are suitable for use as biodegradable single-use packaging and could replace petroleum-based plastics.
The biopolymer chitin is primarily produced as a structural material by crustaceans, insects, and fungi and is – after plant-based cellulose – the second most abundant biopolymer on Earth. Due to its nitrogen content, chitin is already used in agriculture as a fertilizer and soil conditioner or for the production of chitosan. However, commercial use has so far been limited mainly to chitin, which is extracted from crab shells. Yet, the food industry and biotechnology sectors worldwide are generating hundreds of thousands of additional tonnes of chitin-containing residues: insect exoskeletons from insect protein production, mycelium residues from fungal fermentation, and trimmings from mushroom cultivation.
Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB have now succeeded in utilizing insect exoskeletons as well as mycelium-containing residues from fungal fermentation as sources of chitin for producing chitosan. To this end, the institute has established a process chain for chitin processing in which residual and waste streams are treated according to the principles of a biorefinery and converted into valuable materials.
Gentle extraction of chitin from various sources
The composition of chitin-containing residues varies from organism to organism. Crab shells and insect chitin, for example, must be freed from calcium deposits and proteins, while chitin in fungal mycelium is often bound to glucans. “We have adapted our chitin extraction processes to the various waste materials and tailored the necessary separation and processing steps to the respective chemical composition”, explains Thomas Hahn, who has been researching chitin processing at Fraunhofer IGB for many years. This also involved developing or refining analytical methods to assess the success of the processing. Only by knowing the exact chemical composition of the chitin-containing biomass can the valuable raw material be processed in a tailored manner. Using newly established analytical methods, the researcher monitors the chitin content of the intermediate products after each individual purification step.
Sustainable and economical at the same time
To preserve the chemical and physical properties of chitin, it should be separated from the remaining biomass as gently as possible. Hahn therefore prefers to use aqueous media or relies on enzymes to selectively remove impurities. To ensure that the subsequent industrial implementation is also economically viable, the chemist is already evaluating and optimizing the individual process steps at the laboratory scale with a view to upscaling. “If, for example, solvents, reagents, or wash water can be reduced or recycled, this has a positive effect on the overall cost of the process,” Hahn explains.
CHITIN [C8H13NO5] _shelter: textile design prototypes made from spun chitosan fibres
Inspired by the natural origin and properties of the material, the design team at SurrealLabor explored chitosan as a raw material for textile applications. In the CHITIN [C8H13NO5] _shelter project, funded by the Fraunhofer Network “Science, Art, and Design” and with scientific support from Thomas Hahn, they spun chitosan fibres on a laboratory setup built specifically for this purpose using extrusion and wet-spinning processes and processed them into a textile fabric as design prototypes. By establishing, refining, and optimizing chitosan spinning production, the team aims to tap into a new, biobased resource for the textile industry and contribute to a vision of tomorrow’s circular economy. AT
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