The bacteria-generated super-enzyme, which naturally develops the ability to eat plastic, enables complete recycling of bottles. Scientists believe that mixing it with enzymes that break down cotton can result in recycled composite fabrics. Today, millions of tons of such clothes are either dumped in landfills or encroached.
Plastic pollution from the Arctic to the deepest oceans has contaminated the entire planet, and people are now known to consume and breathe microscopic particles. It is currently very difficult to break plastic bottles into their chemical components to make them from old to new, meaning that more new plastics are being made from oil each year.
The super-enzyme was engineered by combining two different enzymes, both of which were found in a plastic-eating bug discovered at a Japanese waste site in 2016. Researchers revealed an engineered version of the first enzyme in 2018, which began breaking down enzymes. Plastic in a few days. But the super-enzyme has to work six times faster.
“When we added enzymes, rather unexpectedly, we experienced a dramatic increase in activity,” Professor John McGeehan said at the University of Portsmouth, UK. “This is a trajectory in an attempt to rapidly make enzymes that are more industrially relevant. But it is one of those stories about learning from nature and then bringing it to the laboratory. ”
French company Carbios revealed a different enzyme in April, originally discovered in a compost pile of leaves, that degrade 90% of plastic bottles within 10 hours, but required heating above 70C it occurs.
The new super-enzymes operate at room temperature, and McGihan said a combination of different approaches could progress towards commercial use: “If we could get better, faster enzymes together and provide companies like Carbios , And work in partnership, then we can start doing so within the next year or two years. ”
The 2018 work determined that the structure of an enzyme, called PETAS, could attack the rigid, crystalline surface of plastic bottles. They found, by accident, that a mutant version worked 20% faster. The new study analyzed a second enzyme found in Japanese bacteria that doubles the rate of breakdown of chemical groups released by the first enzyme.
Bacteria that break down natural polymers such as cellulose have developed this twin approach over millions of years. Scientists thought by combining two enzymes together, it could increase the speed of degradation, and enable them to work more closely together.
It would be impossible for a bacterium to make a linked super-enzyme, because the molecule would be too large. So scientists added two enzymes in the lab and saw another tripling of the motion. New research conducted by scientists from the University of Portsmouth and four American institutions has been published in the journal Proceedings of the National Academy of Sciences.
The team is now investigating how enzymes can be infused to make them work even faster. “There are huge possibilities,” McGeehan said. “We’ve got several hundred in the lab we’re currently gluing together.” A £ 1m test center is now being built in Portsmouth and is currently building a plant in Lyobon.
McGihan said that natural fibers can be broken down by mixing existing fiber-eating plastic enzymes. “Blended Clothes” [of polyester and cotton] Really hard to recycle. We are talking to some big fashion companies that produce these garments, because they are really struggling at the moment. ”
Campaigners say reducing plastic use is key. Recycling workers say that strong, light materials such as plastics are very useful and that true recycling is part of the solution to the pollution problem.
Researchers have also succeeded in finding insects that eat other plastics, such as polyurethane, which are widely used but rarely recycled. When polyurethane breaks down it can release toxic chemicals that will kill most bacteria, but bug detection actually uses the material as food to power the process.