Scientists create plastic-eating ‘super-enzyme’ in war on waste

A potentially transformative breakthrough in the global fight against climate change has been made by scientists in the UK and America.

A plastic-eating ‘super-enzyme’ has been created by scientists at the University of Portsmouth, UK, and the National Renewable Energy Laboratory, US, which could lead to a major reduction in both plastic pollution and greenhouse gases.

The enhanced enzyme is able to dispose of PET (polyethylene terephthalate), the plastic used in soft drinks and fruit juice packaging, as well as PEF (polyethylene furanoate), a sugar-based bioplastic.

PET is non-biodegradable and can take hundreds of years before decomposing.

The same team of scientists had already discovered one enzyme which eats PET called PETase, paving the way for a revolution in recycling.

This enzyme has now been combined with MHETase which is found in the rubbish-dwelling bacteria that live on plastic bottles.

The result is a potent cocktail that breaks down plastic up to six times faster than PETase alone.

Prof John McGeehan of the Centre for Enzyme Innovation at the University of Portsmouth, who led the study, said that it “seemed natural to see if we could use [PETase and MHETase] together, mimicking what happens in nature.”

“Our first experiments showed that they did indeed work better together, so we decided to try to physically link them, like two Pac-men joined by a piece of string,” he said.

The enzymes were studied using Diamond Light Source, a device which harnesses intense beams of X-rays that are 10 billion times brighter than the sun, to observe individual atoms.

The super-enzyme raises the prospect of a step change in the battle against plastic waste, a global blight which has so far proved intractable.

"This is quite a significant leap forward because the plastic that ends up in our oceans today is going to take hundreds of years to break down naturally," Prof McGeehan told PA.

"[Eventually] through sunlight and wave action, it will start to break down into smaller and smaller pieces – and we will end up with microplastics, which is a serious problem for the organisms that live in the environment."

By returning plastic to its original building blocks, it can be made and reused endlessly, reducing reliance on fossil fuels such as oil and gas.

The auspicious discovery also opens up “new avenues for further improvements” said Prof McGeehan. His team is now looking for ways to expedite the process so it can compete with oil.