Enzymes are now indispensable for many industrial sectors. Their potential to naturally refine products or accelerate production processes as catalysts makes protein molecules secret stars of biotechnological processes. Detergent manufacturers in particular can no longer do without these multi-talents. More and more textiles today consist of a mixture of fibers - such as cotton and polyester.  In addition, there are new materials for outdoor textiles made mainly from synthetic fibers. This also poses new challenges for detergents. A particular problem here is the unsightly pilling that occurs on the textile surface after repeated washing.

Synthetic fibers at a glance

The strategic alliance "Functionalization of Polymers" (FuPol) has taken up these and other challenges. Coordinated by the Monheim enzyme specialist evoxx technologies GmbH, nine partners from research and industry have been tackling different challenges for more than five years. These include enzymes for detergents that are used to prevent pilling in the first place or to remove existing pilling in textiles that consist entirely or partly of synthetic fibers. The work of the entire consortium was funded from 2013 to 2018 with a total of 8 million euros by the Federal Ministry of Education and Research (BMBF) as part of the "Industrial Biotechnology Innovation Initiative".

In the first stage until 2016, the project partners were able to identify enzymes that have the potential to nibble off the unpleasant lumps. While browsing through the bioarchive, the biotechnologists of the consortium discovered esterases such as cutinases that break ester bonds and attack natural substrates. "Cutinase is an enzyme used by various fungi to penetrate the cutin layer of leaves," explains Michael Puls, Managing Director of evoxx. "This is a kind of wax layer with which plants protect themselves against pathogens and dehydration. Cutinases are therefore enzymes that attack such layers of wax".

Fight pilling with enzymes

The aim of the second phase, which ended in April 2018, was to improve the activity of the promising candidates and at the same time optimize the production process with a view to industrial application. This work was funded by the BMBF with around 166,000 euros. The focus here was not only on the further development of fiber-lump-degrading enzymes for detergents. The textile industry is also very interested in biotechnological and thus sustainable approaches in the processing of yarns and fabrics, for example in order to combat undesirable residues from fiber production in an environmentally friendly way instead of using chemical substances. "For example, shorter polymer residues lead to difficulties in the subsequent processing of the yarns. These could be removed more sustainably with the aid of enzymes," says Puls.

PET-degrading enzymes identified

In order to improve the activity of the enzymes, the researchers created mutations in the gene encoding the respective enzyme and thus altered its structure. But that' s not all. They modified the so-called binding domain in order to enhance the desired effect of the enzymes. "We have found esterases that degrade PET quite efficiently. We have also developed improved enzyme variants and considerably improved the producibility of the enzymes. This could lead to economic efficiency in the foreseeable future and the application of the enzymes in detergents would then be on the horizon," concludes Puls. Washing tests have already confirmed the so-called anti-pilling effect. The team also succeeded in using optimized PET hydrolysis not only to break down textile fibers, but also to significantly change the surfaces of thin films.