Scientists created a mutant bacterial enzyme that breaks plastic bottles for recycling in hours.
The enzyme, originally discovered in a pile of compost leaves, reduced the bottles into chemical blocks which were then used to produce new high quality bottles. Existing recycling technologies usually produce enough plastic for clothing and rugs.
The company behind the turnaround, Carbios, said it intended to target industrial-scale recycling within five years. He has worked with major companies including Pepsi and L’Oréal to accelerate development. Independent experts have called the new enzyme great progress.
Billions of tons of plastic waste have polluted the planet, from the Arctic to the deepest ocean pit, and pose a particular risk to marine life. Activists argue that reducing the use of plastic is critical, but the company said that the durable and lightweight material was very useful and that true recycling was part of the solution.
The new enzyme was revealed by research published Wednesday in the journal Nature. Work began with the screening of 100,000 microorganisms for promising candidates, including the leaf composting bug, first discovered in 2012.
“He had been completely forgotten, but he turned out to be the best”, said prof. Alain Marty at the University of Toulouse, France, scientific director of Carbios.
Scientists analyzed the enzyme and introduced mutations to improve its ability to break down the PET plastic from which beverage bottles are produced. They also made it stable at 72 ° C, close to the perfect temperature for rapid degradation.
The team used the optimized enzyme to break down a ton of waste plastic bottles, which were 90% degraded in 10 hours. Scientists then used the material to create new plastic food bottles.
Carbios has an agreement with the biotechnology company Novozymes to produce the new enzyme on a scale using mushrooms. He said that the cost of the enzyme was only 4% of the cost of virgin petroleum-based plastic.
Waste bottles also need to be ground and heated before adding the enzyme, so recycled PET will be more expensive than virgin plastic. But Martin Stephan, deputy general manager of Carbios, said that existing sales of recycled plastic of lower quality at a higher price due to the shortage of supply.
“We are the first company to introduce this technology to the market,” said Stephan. “Our goal is to be operational by 2024, 2025, on a large industrial scale.”
He said that a reduction in the use of plastic has been a part of solving the waste problem. “But we all know that plastic brings a lot of value to society, in food, in medical care, in transportation. The problem is plastic waste. “The increase in plastic waste collection has been crucial, Stephan said, with about half of all the plastic going into the environment or landfill.
Another team of scientists revealed in 2018 that they accidentally created an enzyme that breaks down plastic beverage bottles. One of the teams behind this progress, Prof. John McGeehan, director of the Center for Enzyme Innovation at the University of Portsmouth, said that Carbios was the leading enzymatic engineering company to break down PET on a large scale and that the new job it was a great progress.
“It makes possible the possibility of a true biological recycling of PET on an industrial scale. This is a great step forward in terms of speed, efficiency and heat tolerance, “said McGeehan.” It represents a significant step forward for true circular recycling of PET and has the potential to reduce our dependence on oil, reduce emissions. of carbon and energy consumption and encourage the collection and recycling of plastic waste. “
Scientists are also making progress in finding biological methods for breaking down other important types of plastic. In March, German researchers revealed an insect that feeds on toxic polyurethane, while previous work has shown that wax moth larvae – usually bred as fish bait – can eat polythene bags.