One of the major threats to Earth’s life and ecosystems is non-degradable plastic waste which nowadays is found over most of the planet – from the highest mountain peaks to the deepest depths of the oceans.

Hope and hot proteins

But there may be hope ahead. Evamaria Petersen, Associate Professor in the Department of Materials and Production, works on designing proteins and enzymes. Along with her colleagues and students she has designed and produced an enzyme that – for the first time in history – can decompose polycarbonate plastic, a type of plastic that closely resembles PET – the material used to make plastic bottles.

One of the major challenges is that plastic is difficult to decompose, unless it is heated to a point where the structure changes from hard to soft. At the same time, the proteins that can attack the plastic, become highly unstable at temperatures above 60-70 degrees Celsius.

By simulating the process in a computer, the researchers proved that there was a theoretical possibility for enzymes to attack plastic at higher temperatures. This means that it is now – for the first time ever – theoretically possible to decompose polycarbonate plastic using enzymes.

From bio waste to recyclable material

In the lab, the researchers were able to create a functioning prototype version of the enzyme. So far, it is only efficient on polycarbonate plastic, but according to Evamaria Petersen it is only a question of time and resources before similar solutions are developed that work on other types of plastic.

This means that a solution to the environmental challenges related to microplastic and floating plastic waste islands may be just around the corner. Once the plastic is decomposed, it can be used for recycling.

- There is still some work to be done in the lab before the solution is fully functional on more types of plastic, but now we have a functioning concept that we can improve on, says Evamaria Petersen.