Issue 05/2022

Fibres / Textiles /

Fibres / Textiles / Nonwovens Enzymatic degradation of used textiles for biological textile recycling The competence centre Bio4MatPro is part of the Bioeconomy Model Region initiative in the Rhenish Mining Area and funded by the German Federal Ministry of Education and Research (BMBF). The ambition of Bio4MatPro is the biological conversion of different industries such as chemicals, consumer goods, and textiles to become an essential part of a circular (bio)economy. The project EnzyDegTex focuses on the biological transformation of textile recycling using enzymatic degradation and microbial synthesis of chemical base materials and (bio)polymers. Safeguarding economic resources and capacities in the Rhenish Mining Area, Germany, and Europe, the development and expansion of circular economies will be an important aspect in the future. Textile waste is currently disposed of in a linear rather than circular manner. Thus, there is a very high, almost entirely untapped potential for establishing circular economic processes for textiles. More than 1.5 million tonnes of post-consumer textile waste are generated annually from private households in Germany [1]. Recycling textiles poses challenges due to the complexity of textile constructions with diverse, often unknown manufacturer-dependent mixes of different fibre materials, extensive use of additives and dyes, and multi-layer constructions with mechanically inseparable layers. Therefore, recyclin widely used textiles such as polyester-cotton blends is challenging with the recycling approaches available today. Instead, the majority of textile waste is currently downcycled once into low-quality products like painting fleeces or insulation materials, which are disposed of later at the end of their second use phase. The aim of project EnzyDegTex is to close the loop of textile recycling and to provide renewed raw materials from textile waste for the chemical, plastics, and textile industries. The use of enzymes enables selective degradation of materials present in textiles, e.g. polyesters in polyester-cotton blends. Thus, custom-fit recycling processes can be designed using the enzymatic approach, so that complex textile constructions can be treated and respective raw materials returned. For the development of the EnzyDegTex recycling process, process chains with the following sub-steps are being investigated: • Selection and preparation of the textile waste • Development and implementation of the enzymatic degradation • Enrichment and purification of suitable degradation products • Microbial synthesis of chemical base materials and polymers • Development and validation of suitable spinning processes • Development of textile products Enzyme for polyester degradation from textile waste The development of enzymatic degradation processes includes the screening and engineering of promising enzymes that can specifically degrade synthetic polymers or typical additives and dyes from textile material blends. The degradation products are subsequently used as feedstock for the microbial synthesis of textile raw materials. Target raw materials are, for example, mono – and oligomers for the synthesis of melt – or solvent-spinnable polymers. The spinnability of the purified polymers is first evaluated through polymer characterisation measurements and spinning trials on lab-scale spinning plants. Subsequently, melt and solvent spinning processes at a pilot scale are developed for suitable polymers. The resulting yarns are further processed into textile demonstrators as nonwovens, weaves, or knits using classic textile surface manufacturing processes. In addition, the yarn and textile properties are characterised and compared to benchmark products from clothing applications. After three successful project years, the feasibility of biological textile recycling into new chemical base materials and textile products is demonstrated. The implementation of developed products and processes in the Rhenish Mining Area has great potential to play a key role in transforming the linear textile disposal into a circular (bio)economy. With the high availability of textile waste and the local biochemical industry, the region has excellent conditions for creating valuable products from textile waste and new jobs. Moreover, in terms of sustainability, a contribution towards resource efficiency will be made and the amount of incinerated or exported and landfilled textiles will be reduced. By: www.ita.rwth-aachen.de Ricarda Wissel, Stefan Schonauer, Henning Löcken, Thomas Gries ITA Institut für Textiltechnik of RWTH Aachen University, Aachen, Germany Project partners from RWTH Aachen University: Institute of Biotechnology (BIOTEC) Institute of Applied Microbiology (iAMB) Institut für Textiltechnik (ITA) [1] bvse e.V: Bedarf, Konsum, Wiederverwendung und Verwertung von Bekleidung und Textilien in Deutschland, 2020, URL: https://bit.ly/bvse-studie2020 12 bioplastics MAGAZINE [05/22] Vol. 17

4 + 5 April 2023 – Nuremberg, Germany Save the date Call for papers + www.bio-toy.info organized by Media Partner Coorganized by Innovation Consulting Harald Kaeb Speakers of bio!TOY 2021 ®