20
T he ESRF has helped in the development
of an enzyme-embedded plastic that
can biodegrade in a home compost heap.
Can it help solve the plastic crisis?
Plastic production reached a staggering
400 million tonnes in 2022, a
significant portion consisting of
packaging and other single-use items
destined for landfill. The waste is
clearly unsustainable – yet with plastic
having so many unique properties, it is
hard to see an end in sight.
Scientists at the French company
Carbios and the Toulouse
Biotechnology Institute (TBI), also
in France, think they might have
the answer: an engineered enzyme
that can break down the polymers
making up certain plastics into their
constituent monomers. Previously, the
scientists have employed the enzyme
in a recycling plant to turn bottles,
clothes and other items made from
poly(ethylene terephthalate), or PET,
into the raw materials required for new
plastics. Now, they have discovered
that the enzyme can be embedded into
another plastic – polylactide (PLA),
the most widely used bio-sourced
polymer – so that it degrades rapidly
under domestic compost conditions.
According to Alain Marty, the
chief scientific officer of Carbios, the
result is down in part to a long-term
collaboration with the ESRF and
its structural-biology beamlines. In
the latest work, the scientists took
some of their data from experiments
at the ESRF’s ID23-1 beamline.
Diffraction data helped us unveil the
structure of the enzyme to understand
better the relation between its
structure and function The resulting
enzymeengineering work leads to
an efficient enzyme that allows the
plastic to selfbiodegrade at room
temperature
Usually PLA degrades very slowly
in home compost and soil Embedded
with the new enzyme however its
composting time is just 2024 weeks
Published in July the results reveal
that the enzymes function is
not affected when it is heated to
170°C, meaning that the PLA can
be extruded into whatever shape
necessary; nor does the final material
degrade prematurely when used in the
long-term storage of sauces, yoghurt,
coffee and other foodstuffs (Nature
631 884).
Since the results were published,
Carbios has announced the signing
of a long-term contract with another
French company, Sleever, to develop
the enzyme-embedded PLA for the
manufacture of “shrinksleeve” labels,
which are often used to fully seal the
tops of bottles and prevent tampering.
Meanwhile its recycled PET has been
employed by manufacturers including
the French perfumer LOccitane
As Carbios expands its portfolio
of enzymatic solutions beyond
PET enzymeembedded PLA
represents a major leap forward
addressing a critical gap in the
market for compostable plastic
says Emmanuel Ladent the Carbios
chief executive officer
Jon Cartwright and Montserrat
Capellas Espuny
Bye bye plastic?
“Usually, PLA
degrades slowly.
Embedded with the
new enzyme, its
home-composting
time is just
20–24 weeks”
December 2024 ESRFnews
S L E E V E R
t
The plastic of this L’Occitane bottle is made from PET plastic
that was recycled using Carbios technology.