Hard plastics are an urgent threat to the global community. Every year, 300 million tonnes of plastic are produced worldwide, but the material is difficult to break down, and this is a major problem according to Professor Daniel Otzen from the Interdisciplinary Nanoscience Centre (iNANO) at Aarhus University.

"The world is drowning in plastic, and we don't know how to handle this crisis. We produce so much plastic that we cannot keep up and do something about it. Plastic is piling up, and we have to find a way to deal with this problem," says Daniel Otzen.

The professor now has a chance to find solutions to the problem as the Novo Nordisk Foundation has heard his call for action and has granted DKK 57 million for a new centre at Aarhus University named "Center for enzymatic deconstruction of thermoset plastics for a sustainable society (En’Zync)”.

Plastic research will be a state of mind rather than a project

Plastic is a relatively new material that has only been around for 60 years or so. But despite its short lifespan, it has become an elemental part of our society because it is a strong material that is hard to break down. Plastic is made up of long chains of molecules, and those chains become stronger and stronger when they are interlinked, which also makes them very hard to break down. Today, plastic is typically burnt, buried or thrown into the sea.

"The fact that we can’t handle the amount of plastic that exists in the world is a huge problem, and we have to solve it for the sake of the planet. Science can help find solutions, and, for me, it’s almost therapeutic to be able to contribute to solving such a major global challenge," says Daniel Otzen.

Together with colleagues from both Denmark and Portugal, the professor will try to find methods to break down plastic. He thinks that the project will be more than just something he does for work.

"The centre will be a game changer for the research activities of the participating researchers, and we hope, of course, that we can make a significant difference to plastic research. We’ll spend a lot of time learning about the material and finding solutions. This will be an important and very ambitious project, and it will become a state of mind for us rather than just a project," says the professor with a smile.

Plastic-like enzymes are the key

The first step on the path to finding a solution is to find enzymes that can break down plastic. Enzymes are molecules that can be found in e.g. living mechanisms where they can spur on processes such as reconstruction and degradation. Some types of plastic have bonds that resemble natural bonds found in e.g. fats and proteins, and enzymes that can break down fats and proteins already exist. These enzymes have already naturally developed the ability to break down certain types of plastic. Daniel Otzen therefore believes that the enzymes can be the key to solving the plastic crisis.

En'Zync will develop methods to find these enzymes by feeding them substrates that resemble plastic. The substrates will change colour when they are broken down by enzymes, and the enzymes that are found in this way will be exposed to increasingly plastic-like substrates, so that the researchers can be sure that they are worth focusing on.

"Figuratively speaking, we start by throwing out a large net to catch a lot of enzymes. Some of the enzymes may only have a weak ability to break down plastic. We’ll keep narrowing the field until we’re left with the most effective plastic-eating enzymes. This will also help us determine nature’s own potential of breaking down enzymes and plastic itself," explains Daniel Otzen.

Once the enzymes have been found, researchers will learn more about how plastic is broken down at molecular level, and how enzymes bind to plastic. The breakdown will take place both in physical experiments and in computer simulations because it is necessary to have data from simulations to fully understand the process taking place in the physical experiments.

Credit: Ambitious research

The Novo Nordisk Foundation Challenge Programme awards a total of DKK 337 million to ambitious projects that can help solve society's biggest challenges, and Daniel Otzen is one of only six experienced researchers who will receive a Novo Nordisk Foundation Challenge Programme grant this year.

"Being acknowledged by the foundation in this way means so much. It’ll really make a difference, both for plastic research, which is relatively new, and for the global community as a whole. We need to solve the plastic crisis and we need to find out how we can help clean up after ourselves, and with this grant, we can find the solutions to do so," says Daniel Otzen.

• Daniel Otzen, centre director and professor, Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, email: dao@inano.au.dk, tel.: + 45 20725238
• Associate Professor Søren Skou Thirup, Department of Molecular Biology and Genetics, Aarhus University.
• Professor Peter Westh, Department of Biotechnology and Biomedicine, Technical University of Denmark
• Professor Uffe Hasbro Mortensen, Department of Biotechnology and Biomedicine, Technical University of Denmark
• Professor Jens Preben Morth, Department of Biotechnology and Biomedicine, Technical University of Denmark
• Jacob Serup Ramsay, team manager, Products and Materials Chemistry, Danish Technological Institute
• Alexander Sandahl, consultant, Products and Materials Chemistry, Danish Technological Institute
• Anders Lindhardt, product manager, Products and Materials Chemistry, Danish Technological Institute
• Manja Annette Behrens, team manager, Products and Materials Chemistry, Danish Technological Institute
• Professor Maria João Ramos, Department of Chemistry and Biochemistry, Porto University
• Associate Professor Pedro Alexandrino Fernandes, Department of Chemistry and Biochemistry, Porto University