Scientists designed an enzyme that can break down the most common plastic waste in our lives, making it possible to solve one of the world's biggest environmental problems. The discovery solved millions of tons of polyethylene terephthalate ( PET) Recycling of made plastic bottles, or to decompose PET waste that has been in the environment for hundreds of years.
The picture shows Professor John McGeehan and his colleagues inadvertently designed an enzyme that is better than the enzymes used in nature to degrade plastic waste.
Prof. John McGeehan of the University of Portsmouth and Dr. Gregg Beckham of the US Department of Energy's Renewable Energy Laboratory (NREL) studied the crystal structure of a recently discovered enzyme (PETase) used to degrade PET, and learned about it through 3D information. How it works. During the course of the study, they inadvertently designed an enzyme that performs better than enzymes that evolved in nature to degrade plastics.
Now, researchers are working on further improving this enzyme to make it sustainable for plastics decomposition in factories. They have made a breakthrough in the study of the structure of natural enzymes and believe that this enzyme is a waste recovery in Japan. The center was trained to allow bacteria to degrade plastics as a food source.
In the 1940s, PET plastics did not take long time in nature, so the research team is committed to identifying the development of enzymes and improving it.
The ultimate goal of the study was only to determine the structure of the enzymes, but they never thought that they would go further and unexpectedly designed an enzyme that could better degrade PET plastics.
McGeehan said: 'In the basic scientific research, accidental often plays an important role, so our accidental discovery is also normal.'
Although the improvement is modest, this accidental discovery suggests that there is still more room for improvement of these enzymes, which will make us more confident in finding a solution for recycling these piles of waste plastic waste.
The picture shows the electron microscope image of the enzyme-degraded PET plastic
The research team can now apply protein engineering and evolutionary techniques to continue improving enzymes.
University of Portsmouth, the US Department of Energy's Renewable Energy Laboratory (NREL), and the British scientists of the Diamond Light Source have collaborated to observe a single atom using a synchrotron that uses a X-ray beam that is 10 billion times brighter than sunlight.
The photo shows Benjamin Luethi checking the Diamond Light Source's I23 beam line, which played an important role in the discovery of enzymes.
Use their ultra-high resolution 3D model to generate accurate PETase enzymes using the I23 beam line in their latest laboratory.
Professor McGeehan said: 'Diamond Light Source recently created one of the most advanced X-ray beam lines in the world. Through this device we can see the 3D atomic structure of PETase in an incredible way. The internal operation of the catalyst provides us with a blueprint to design faster and more efficient enzymes.
Evolutionary PETase enzyme is better than native PETase enzyme
With the help of computational modelling scientists at the University of South Florida and the University of Campinas, Brazil, the team found that the PETase enzyme appears to be very similar to cutinase, but the PETase enzyme has some unusual features, including more open active sites. , Can adapt to artificial polymers and not just natural polymers. These differences indicate that the PETase enzyme may have evolved in PET-containing plastics in order to degrade PET plastics. To test this hypothesis, the researchers mutated the active site of the PETase enzyme to make it more like cutinase.
Researchers have unexpectedly discovered that the evolved PETase enzyme is better than native PETase enzymes in degrading PET plastics.
It is worth noting that this enzyme can also degrade furose dicarboxylic acid polyethylene glycol ester plastic (PEF), which is also considered to be a substitute for glass beer bottles as a biological substitute for PET plastics.
The study was funded by the University of Portsmouth, the US Department of Energy's Renewable Energy Laboratory (NREL) and the Biotechnology and Biological Sciences Research Council (BBSRC).