As you've no doubt noticed, there's a worryingly large amount of plastic pollution,
and scientists are working hard to find ways to use plastic without
causing so much long-term damage to the environment around us.
A
new study outlines the use of a specially created enzyme variant that
vastly reduces the time it takes to break down the components of
plastics.
We could even use the enzyme variant to clean up sites contaminated by plastic pollution, say the team that developed it.
In
tests, products made from the polymer polyethylene terephthalate (PET)
were broken down in a week and, in some cases, 24 hours – these are
products that can take centuries to degrade properly in natural
conditions.
"The possibilities are endless across industries to leverage this leading-edge recycling process," says chemical engineer Hal Alper from the University of Texas at Austin.
"Beyond
the obvious waste management industry, this also provides corporations
from every sector the opportunity to take a lead in recycling their
products."
The
team has called the enzyme FAST-PETase (functional, active, stable, and
tolerant PETase). They developed the enzyme from a natural PETase that
allows bacteria to degrade PET plastic and modified it using machine learning to pinpoint five mutations that would enable it to degrade the plastic faster under different environmental conditions.
Watch video: https://youtu.be/jXVSpuclZt4
Once
the enzyme variant did its job of cutting the plastic down into its
basic molecular units (depolymerization), the researchers then
demonstrated they could put the plastic back together again
(repolymerization) using chemical processes to create new plastic
products.
Finding
FAST-PETase involved the study of 51 different post-consumer plastic
containers, five different polyester fibers, and fabrics and water
bottles made from PET.
In
tests on all of these products, the enzyme variant proved its
effectiveness and at temperatures less than 50 degrees Celsius (122
degrees Fahrenheit).
"When
considering environmental cleanup applications, you need an enzyme that
can work in the environment at ambient temperature," says Alper. "This requirement is where our tech has a huge advantage in the future."
PET
is in many consumer packaging, from textiles to soda bottles. On its
own, it's thought to make up around 12 percent of all global waste. If
that figure wasn't frightening enough, try this one: Globally, less than 10 percent of all plastics have been recycled.
The
introduction of FAST-PETase could go some way to helping. The
researchers say that it's relatively cheap, portable, and not too
difficult to scale up to the sort of industrial levels that would be
required.
Right
now, the most common methods for disposing of plastic are to throw it
in a landfill where it rots at a very slow rate, or to burn it – which
costs a lot, uses up plenty of energy, and fills the atmosphere with
noxious gas. It's clear that alternative strategies are desperately needed, and this could be one of them.
"This
work really demonstrates the power of bringing together different
disciplines, from synthetic biology to chemical engineering to artificial intelligence," says biochemist Andrew Ellington from the University of Texas at Austin.
The research has been published in Nature.