Damian Carrington: Scientists create mutant enzyme that recycles plastic bottles in hours
A mutant bacterial
enzyme that breaks down plastic bottles for recycling in hours has been created
by scientists. The enzyme, originally
discovered in a compost heap of leaves, reduced the bottles to chemical
building blocks that were then used to make high-quality new bottles. Existing
recycling technologies produce plastic only good enough for clothing
and carpets.
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The company behind the
breakthrough, Carbios, said it was aiming for industrial-scale recycling within
five years. It has partnered with major companies including
Pepsi and L’Oréal to accelerate development. Independent experts
called the new enzyme a major advance. Billions of tonnes of
plastic waste have polluted
the planet,
from the
Arctic to the deepest
ocean trench, and pose a particular risk to sea life. Campaigners say
reducing the use of plastic is key, but the company said the strong,
lightweight material was very useful and that true recycling was part of the
solution.
The new enzyme was
revealed in research
published on Wednesday in the journal Nature. The work began with the
screening of 100,000 micro-organisms for promising candidates, including the
leaf compost bug, which was first discovered in 2012. “It had been
completely forgotten, but it turned out to be the best,” said Prof Alain Marty
at the Université de Toulouse, France, the chief science officer at Carbios. The scientists
analysed the enzyme and introduced mutations to improve its ability to break
down the PET plastic from which drinks bottles are made. They also made it
stable at 72C, close to the perfect temperature for fast degradation.
The team used the
optimised enzyme to break down a tonne of waste plastic bottles, which were 90%
degraded within 10 hours. The scientists then used the material to create new
food-grade plastic bottles. Carbios has a deal
with the biotechnology company Novozymes to produce the new enzyme at scale
using fungi. It said the cost of the enzyme was just 4% of the cost of virgin
plastic made from oil....
https://www.theguardian.com/environment/2020/apr/08/scientists-create-mutant-enzyme-that-recycles-plastic-bottles-in-hours