<
https://www.theguardian.com/environment/2023/sep/28/plastic-eating-bacteria-enzyme-recycling-waste>
"In 2001, a group of Japanese scientists made a startling discovery at a
rubbish dump. In trenches packed with dirt and waste, they found a slimy film
of bacteria that had been happily chewing through plastic bottles, toys and
other bric-a-brac. As they broke down the trash, the bacteria harvested the
carbon in the plastic for energy, which they used to grow, move and divide into
even more plastic-hungry bacteria. Even if not in quite the
hand-to-mouth-to-stomach way we normally understand it, the bacteria were
eating the plastic.
The scientists were led by Kohei Oda, a professor at the Kyoto Institute of
Technology. His team was looking for substances that could soften synthetic
fabrics, such as polyester, which is made from the same kind of plastic used in
most beverage bottles. Oda is a microbiologist, and he believes that whatever
scientific problem one faces, microbes have probably already worked out a
solution. “I say to people, watch this part of nature very carefully. It often
has very good ideas,” Oda told me recently.
What Oda and his colleagues found in that rubbish dump had never been seen
before. They had hoped to discover some micro-organism that had evolved a
simple way to attack the surface of plastic. But these bacteria were doing much
more than that – they appeared to be breaking down plastic fully and processing
it into basic nutrients. From our vantage point, hyperaware of the scale of
plastic pollution, the potential of this discovery seems obvious. But back in
2001 – still three years before the term “microplastic” even came into use – it
was “not considered a topic of great interest”, Oda said. The preliminary
papers on the bacteria his team put together were never published.
In the years since the group’s discovery, plastic pollution has become
impossible to ignore. Within that roughly 20-year span, we have generated 2.5bn
tonnes of plastic waste and each year we produce about 380 million tonnes more,
with that amount projected to triple again by 2060. A patch of plastic rubbish
seven times the size of Great Britain sits in the middle of the Pacific Ocean,
and plastic waste chokes beaches and overspills landfills across the world. At
the miniature scale, microplastic and nanoplastic particles have been found in
fruits and vegetables, having passed into them through the plants’ roots. And
they have been found lodged in nearly every human organ – they can even pass
from mother to child through breast milk.
Current methods of breaking down or recycling plastics are woefully inadequate.
The vast majority of plastic recycling involvesa crushing and grinding stage,
which frays and snaps the fibres that make up plastic, leaving them in a
lower-quality state. While a glass or aluminium container can be melted down
and reformed an unlimited number of times, the smooth plastic of a water
bottle, say, degrades every time it is recycled. A recycled plastic bottle
becomes a mottled bag, which becomes fibrous jacket insulation, which then
becomes road filler, never to be recycled again. And that is the best case
scenario. In reality, hardly any plastic – just 9% – ever enters a recycling
plant. The sole permanent way we’ve found to dispose of plastic is
incineration, which is the fate of nearly 70 million tonnes of plastic every
year – but incineration drives the climate crisis by releasing the carbon in
the plastic into the air, as well as any noxious chemicals it might be mixed
with.
In the years after their discovery, Oda and his student Kazumi Hiraga, now a
professor, continued corresponding and conducting experiments. When they
finally published their work in the prestigious journal
Science in 2016, it
emerged into a world desperate for solutions to the plastic crisis, and it was
a blockbuster hit. Oda and his colleagues named the bacterium that they had
discovered in the rubbish dump
Ideonella sakaiensis – after the city of
Sakai, where it was found – and in the paper, they described a specific enzyme
that the bacterium was producing, which allowed it to break down polyethylene
terephthalate (PET), the most common plastic found in clothing and packaging.
The paper was reported widely in the press, and it currently has more than
1,000 scientific citations, placing it in the top 0.1% of all papers."
Via
What Could Go Right? October 5, 2023:
https://theprogressnetwork.org/natural-disaster-deaths-declining/
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
