Post by account_disabled on Feb 21, 2024 22:12:27 GMT -5
A new superenzyme that breaks down plastic bottles six times faster than normal has been created by scientists and could be used for recycling within a year or two. According to The Guardian , the superenzyme, derived from bacteria that naturally evolved the ability to eat plastic, allows for complete recycling of bottles. Scientists believe that combining it with enzymes that break down cotton could also allow mixed fabric clothing to be recycled. Today, millions of tons of such clothing are thrown into landfills or incinerated. Plastic pollution has contaminated the entire planet, from the Arctic to the deepest oceans, and people are now known to consume and breathe microplastic particles. It is currently very difficult to break down plastic bottles into their chemical constituents to make new ones from old ones, meaning that more new plastic is created from petroleum every year. How was this superenzyme created? The superenzyme was designed by joining together two separate enzymes, both found in the plastic-eating bug discovered in a Japanese landfill in 2016. Researchers revealed an engineered version of the first enzyme in 2018, which began breaking down plastic within a few days. But the superenzyme works six times faster. When we linked the enzymes quite unexpectedly, we got a dramatic increase in activity.
This is a trajectory to try to make faster enzymes that are more industrially relevant. But it's also one of those stories about learning from nature, and then taking it to the laboratory. John McGeehan, professor at Europe Cell Phone Number List the University of Portsmouth, United Kingdom. French company Carbios revealed a different enzyme in April, originally discovered in a pile of composting leaves, that degrades 90% of plastic bottles in 10 hours, but requires heating above 70ºC. The new superenzyme works at room temperature, and McGeehan said combining different approaches could accelerate progress toward commercial use: If we can make better and faster enzymes by linking them together and providing them to companies like Carbios, and work in partnership, we could start doing this within a year or two. John McGeehan, professor at the University of Portsmouth, United Kingdom. Studies on the enzyme The 2018 work had determined that the structure of an enzyme called PETase can attack the hard, crystalline surface of plastic bottles. They discovered, by accident, that a mutant version worked 20% faster. The new study looked at a second enzyme, also found in Japanese bacteria, that doubles the rate of breakdown of chemical groups released by the first enzyme.
Bacteria that break down natural polymers like cellulose have developed this dual approach over millions of years. Scientists thought that by connecting the two enzymes together, they could increase the rate of degradation, and allow them to work more closely. The linked superenzyme would be impossible for a bacteria to create, as the molecule would be too large. So scientists connected the two enzymes in the lab and watched the speed triple. The new research by scientists at the University of Portsmouth and four US institutions is published in the journal Proceedings of the National Academy of Sciences. The team is now examining how the enzymes can be tuned to work even faster. " There is enormous potential ," McGeehan said. " We have several hundred in the lab that we are currently putting together ." A million-pound testing center is being built in Portsmouth and Carbios is building a plant in Lyon. Combining plastic-eating enzymes with existing ones that break down natural fibers could allow the mixed materials to be completely recycled, McGeehan said. Mixed fabrics (polyester and cotton) are really difficult to recycle.