The European Commission presented its “European Green Deal” to make Europe the “first continent to present a comprehensive architecture” to say goodbye to CO₂ by mid-century and turn the climate crisis into an opportunity for more sustainable growth. AITIIP is leading research and innovation lines about new sustainable materials and circular economy including the study of the materials’ end of life following the European programmes such as the Green Deal and the previous Circular Economy package. The projects coordinated by AITIIP, ENXYLASCOPE and BIZENTE, are examples where sustainable materials and sustainable end of life processes are reached thanks to enzymes.

AITIIP is a Technological Centre with more than 20 years experience in the market of plastic products and their transformation processes. AITIIP has been coordinating and participating in European and national projects related to sustainable materials and their transformation for different sectors  for more than 10 years. AITIIP is leading research and innovation lines about new sustainable materials and circular economy including the study of the materials’ end of life following the European programmes such as the Green Deal and Circular Economy.

The European Commission adopted the new circular economy action plan (CEAP) in March 2020. It is one of the main building blocks of the European Green Deal, Europe’s new agenda for sustainable growth. The EU’s transition to a circular economy will reduce pressure on natural resources and will create sustainable growth and jobs. It is also a prerequisite to achieve the EU’s 2050 climate neutrality target and to halt biodiversity loss. The planned adoption date for several initiatives under the action plan was set between 2021-2022 so there is a lot of work ahead us to help companies reach the European climate objectives.

EnXylaScope is one example of a project leading the sustainable change to new materials and sustainable processes. Novel enzymes for debranching xylan coming from agricultural wastes will be discovered. Productions systems for these enzymes will be optimised and the enzymes will be applied to produce a debranched (water-insoluble) form of xylan that has properties which make it suitable as ingredients in a scope of consumer products. The debranched xylan will be further modified, using available enzymes, to confer functionalities that expand the range of potential consumer products. Grafting of fatty acid groups on to extracted xylan, WIS-xylan, and Xyl-Phe will be tested using lipase from Candida antartica and METGEN’s laccases. The xylans subjected to grafting will be tested by for degree of substitution, molecular weight, and other properties. AITIIP will study the mechanical and thermal properties. In total, 3 types of enzymatically modified xylan will be obtained and will be tested for 6 consumer products in 3 sectors (cosmetics, personal care, nutraceuticals). AITIIP is working already in the envisaged exploitation of the results of the project to speed up their reception in the market.

On another hand, plastic waste is one of the main threats to our ecosystems. Currently, the world production of plastics exceeds 350 million tons, approximately 85% corresponding to the production of thermoplastics and 15% to the production of thermosets.

That is why, in recent years, several initiatives, efforts and investments have been launched to increase the recycling rate or promote materials with more controlled biodegradation in the thermoplastics sector. Thermoset composites, unlike thermoplastics, cannot be melted, making it difficult to reuse them. In thermoset materials, the chemical bonds that are generated produce an irreversible three-dimensional network through the application of an energy source, usually heat, in a process called curing. The material hardens permanently making it difficult to recycle.

For this reason, there are far fewer strategies and technologies available to manage the end of life of thermoset plastics and composites, making them a challenge for waste management. Today, these materials are either stored in landfills (24.9%), including airplane, wind blade, and railway graveyards; or they end up being valued for energy (42.6%), where the resin is incinerated and only the reinforcement is recovered, although it is usually damaged and cannot be reused for the same purpose.

In this line of work, AITIIP is leading another project related to enzymes: BIZENTE[1]. This project presents a biological alternative to chemical recycling, a completely new approach based on the development of enzymes that selectively depolymerize the resin without damaging the fibre. Currently, there are no known enzymes that naturally attack these materials. However, technologies such as directed molecular evolution allow the design of enzymes with improved characteristics and new enzymatic functions not present in natural environments. Therefore, it is possible to design enzymes with improved catalytic capabilities, greater specificity and stability at certain temperatures or organic solvents. BIZENTE project is working with low molecular weight model compounds in the laboratory that contain all the structural characteristics of the target resins, so that enzymes can be determined and trained to break the bonds of these compounds and study the products obtained. TUDELFT (also partner in ENXYLASCOPE) is studying soluble models using the customised enzymes and different model compounds which contain the key functional groups of the studied resins to determine how the enzymes attack the bonds of these functional groups and what products will be obtained.

Once the enzymes with the greatest degradation potential of the selected resins are selected (the project works with epoxy, vinyl ester and polyester resin), they will be tested in a bioreactor with real composite materials. In this way, the real products obtained are studied and different strategies are proposed for the recovery of both the monomers or chemical blocks and the fibres.

In conclusion, new materials and new processes leaded by new enzymes can be obtained helping to contribute to the European Climate and sustainability goals.

[1] The BIZENTE project have received funding from the Bio–Based Industries Joint Undertaking (JU) within the framework of the European Union’s Horizon 2020 research and innovation program under grant agreement No. 886567.