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Insect chitin makes textile production more sustainable

Insects have an external skeleton composed mainly of chitin. Chitin is a long-chain polysaccharide with functional groupsthat make it a valuable biopolymer for a broad range of applications. Chitin is an almost inexhaustible resource, as it isconstantly produced in huge quantities throughout nature. At present, chitin is mainly produced from fish industry waste.The extraction of insect chitin has not yet been considered. Researchers from the Fraunhofer Institute for InterfacialEngineering and Biotechnology (IGB) and six cooperation partners are working on developing a biotechnological method formaking insect chitin usable for coating textiles.

Chitin is a biopolymer composed of long acetylglucosaminechains that is produced by many organisms. For example, itis a characteristic component of the external skeleton ofinsects, crustaceans and the cell walls of fungi. This makeschitin one of the most abundant polymers on earth. Severalbillion tons of chitin are produced naturally every year.Theoretically, chitin is an almost inexhaustible rawmaterial. However, it is still largely seen as waste, ratherthan a raw material. While attempts to process shrimpshells for use as raw materials in the polymer industry havebeen quite successful, with insect chitin, the situation isdifferent as methods for sustainably refining the polymerare currently unavailable. Neither has any economicallyviable chitin resource been available until recently.

Dr.-Ing. Susanne Zibek, Dr.-Ing. Thomas Hahn and theirteam of researchers from the Fraunhofer Institute forInterfacial Engineering and Biotechnology (IGB) in Stuttgartare working with six national and international partnerinstitutions on a project called ChitoTex. The project beganin 2015 and is coordinated by Dr. Zibek. The researchersare looking into ways of refining insect chitin and using itas functional coating for yarn and fabrics in the textileindustry. They use chitin produced by Hermetia illucens, theblack soldier fly, which is bred by a Dutch company calledProtix. The company breeds the insects on GMP+-certifiedplant residues from the food and feed industry to producehigh-quality protein for animal feed. The same high-qualityprotein is also being considered for use as a component ofhuman food,” says Hahn. “As soon as we can be sure thatno contaminants or microorganisms are present in thefinal product, this type of protein food will also be suitableas human food.”

Dr.-Ing. Thomas Hahn is looking for ways to make insect chitin usable. © Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB)

Insect breeding on waste residues

At the start of the project, the chemists from Stuttgart received a variety of chitin samples from the Dutch insect company inwhich they determined the quantity of chitin. Samples with the largest quantities were then selected for further processing. “Inan earlier project, the researchers had isolated two microorganisms with chitinolytic capacities,” said Hahn. “In addition tocoordinating the ChitoTex project, our group is also focused on developing methods for refining insect chitin, as well asenzymatically degrading chitosan and chemically modifying it. We are working on this with our project partners. We are alsocarrying out chitin analyses.” The IGB researchers also plan to create decentralised chitin resources where chitin is needed,

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especially in view of its future use in human food. “Two kilogrammes of insects can be produced from one kilogramme of foodwaste. This is much more sustainable than beef or pork production,” says the scientist. “Insect chitin will be a by-product.“

The project is now halfway through, and a large part of it has already been successfully completed: the researchers’ Norwegianproject partner, the Norwegian University of Life Sciences, has identified several chitinolytic genes, which are now beingexpressed by the group’s Austrian project partner, an enzyme specialist called EUCODIS Bioscience GmbH. “At the IGB, we willlater focus on processing insect chitin into chitosan using a special enzyme cocktail,” says Hahn. Chitosan is a versatile rawmaterial for producing many different biopolymers. At present, the IGB researchers and their partners from the textile industry,Reutlingen-based Dr. Petry GmbH and Lauchringen-based Lauffenmühle GmbH & Co KG, are studying ways of functionalisingchitosan and using it for coating textiles. The researchers hope that natural chitosan will contribute to greater sustainability inthe textile industry, which is currently very chemical-based.

The IGB researchers use black soldier fly (Hermetia illucens) cocoons as a chitin source for producing new high-quality biopolymers. © Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB)

Insect chitin replaces petrochemical source materials

“Our aim is to create better and more environmentally friendly products for the textile industry,” says the chemist. Insect chitin-based products can be used for textile sizing which, amongst other things, changes the wear resistance of textiles. Coatingtextiles with chitosan protects them and prevents damage.” In addition, the researchers want to establish a method forfunctionalising chitosan amine groups; the amine groups could then be used as an anchor for other molecules, such as thosethat increase the wash resistance of textiles, thus introducing another functionality. A first type of coating with promisingcharacteristics has already been produced, but the researchers are not yet happy with the results. Further optimisation work istherefore needed. Once the desired properties have been achieved, the researchers will increase the production scale andtransfer the positive characteristics of chitosan such as its antimicrobial effect to textiles. In contrast to other substances such assilver threads, which are incorporated into functional socks, chitosan is non-toxic and biodegradable.

Dr. Hahn is convinced that in future, there will be a wide range of products involving the use of insect chitin, in both the textileand other industries. Hahn’s project partners from the textile industry are extremely open-minded as far as the use ofbiotechnologically produced substances is concerned. However, at present 90 percent of all substances used are still ofpetrochemical origin. Although cellulose fibres are already widely used in the textile industry, they are coated with substances

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that are not sustainably produced.

1 Sizing: In the textile industry, sizing liquor is applied to yarn in order to make the threads smoother and more resistant to mechanical stress, thus making it less liable tobreak.

28.02.2017 – Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB): We kindly thank the GermanMinistry of Education and Research (BMBF) for funding in the transnational ERA-IB project ChitoTex (Grant agree number:031A567A)

Article

07-Dec-2016Dr. Petra Neis-Beeckmann© BIOPRO Baden-Württemberg GmbH

Further information

Dr.-Ing. Thomas HahnFraunhofer Institute for Interfacial Engineering and Biotechnology (IGB)Nobelstr. 1270569 StuttgartPhone: +49 (0)711 970-4159E-mail: thomas.hahn(at)igb.fraunhofer.de

The article is part of the following dossiers

Sustainable textiles

Innovative textiles made possible by biotechnology

Fraunhofer IGBChitoTex

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industrialbiotechnology

textiles biomass biopolymers biomaterials renewablematerials

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