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Nature reflects our nature
Can plastics be degraded ?
My hands are on the keypad of my laptop and I am
typing by pressing those small keys and I am aware
that I am using a device with many parts of it made
by Plastics. Plastic mostly related to words like Pli-
able (Stretchable, malleable) and Polymers (of many
parts) has become an indispensable part of our life. It
is used in each part with which we strike time and again
in our daily life. Annually we manufacture about 3 mil-
lion ton of plastics. Looking at the statistics of 2017,
world plastics production totaled around 348 million
metric tons and the rate of manufacture is growing
exponentially. The plastics (Focusing; Polyethylene
terephthalate (PET)) comes with the packaging of
clothes, utensils, mineral water, drinks, other devices
(laptop, pen, watches, etc.) and vast use in scientific
discovery and other technical fields. These products
are most essential for us so we can agree that the
plastics are used for the vital works but what about the
work done by the plastics towards the environment?
In a cycle of nature everything dies, deteriorates
once to keep up the balance but what about plastics?
Are Plastics that idiosyncratic stuff that violates this
very ethic and lasts forever in the environment? The
answer was yes before 2012 and was only believed
to maintained by following 5R principles (Reduce,
Reprocess, Reuse, Recycle, Recover) but by 2012
a group of Student from Yale University searched for
plants within the Amazon and then cultured the mi-
croorganisms within the plant tissues and ended up
by finding pestalotiopsis, which could effectively de-
grade polyurethane(used mostly in hard plastics and
foam) and again in 2016 a team at Kyoto University
had found a bacterium that degrades and assimilates
poly(ethylene terephthalate)(General plastic bottles).
By scrambling around sediments, soil, wastewater
and other piles of wastes they took 250 samples in
5 years and isolated a bacteria “Ideonella Sakiensis”
that can live on Plastics. The second discovery of
2016 was more effective in comparison with the first
one as Ideonella Sakiensis could grow easily but it
is not that easy to cultivate fungi pestalotiopsis. The
student of Kyoto also identified the enzymes that are
used by sakiensis to breakdown the PET. They iden-
tified a gene in the DNA of bacteria that is responsi-
ble for the production of PET degrading enzyme. The
enzyme was named as PETase. The PETase can
breakdown certain chemical bonds in PET, leaving
tiny molecules that can be absorbed by bacteria us-
ing carbon in them as a food source. Different groups
of people of many countries like Korea, China, UK,
and Brazil are in continuous research to find out the
mechanisms of the enzyme and trying to make it
work faster by manipulating its active parts. This is
unusual that the enzyme that is being discovered
should work faster than the natural one. But still, this
achievement shows that these bacteria are recent-
ly evolved to survive on the man-made plastic which
can be an evolutionary approach to engineer an op-
timized form of PETase. Despite the negative impact
of plastics we mostly depend on Plastics and if the
rate of enzyme formation increases then the durabili-
ty of plastic products decreases.
What if the bacteria started eating all the plastic struc-
tures of the environment in an uncontrolled way that
were made to last for the number of years? Will our
survival become possible without any plastic prod-
ucts? The situation can arise as we are not that good
to outplay with bacteria. (Antibiotics example). But
perhaps looking at today’s worst condition of Envi-
ronment made by plastics, the identification of bacte-
ria like Ideonella sakiensis can be a good fortune for
all the living creatures.
Samyog Dhakal
B.Sc.Environmental Science
2nd Year (Batch-2017)
Nature and Social Concern Society
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