Plastic-Eating Enzymes

Key concepts:

• PET (used to make plastic bottles) takes hundreds of years to degrade
• French team with a PET-consuming enzyme
• UK team with a PET-consuming enzyme
• examples of bio-mimicry inspired by mealworms and waxworms

The Goal: If PET could be recycled, rather than using fossil fuels to create new plastic, this would not only reduce plastic pollution but also address climate change. PET takes hundreds of years to degrade in the environment. A French team and a UK team are both racing to discover a super enzyme that can consume and break down the plastic PET (polyethylene terephthalate) in plastic bottles.

In 2021, Carbios, a French company, will test its PET-eating enzyme at a demonstration plant near the city of Lyon, described in “An engineered PET depolymerase to break down and recycle plastic bottles” on April 8, 2020 in Nature. On May 21, 2020 Nature Biotechnology covered this breakthrough as Closing the recycling circle: capturing the value back from plastic waste has been the holy grail of recyclers. Biotechnology is taking us closer to a solution.

Other possible solutions include the tiny waxworm, which can consume not only PET (polyethylene) a common and non-biodegradable plastic currently clogging up landfills and seas.

In September 2020, CNN reported on a Portsmouth, UK team with a super-enzyme that can consume waste plastic.

Their new enzyme, PETase, can break it down into its building blocks in a few days. John McGeehan, project co-lead and Director of the Centre for Enzyme Innovation at the University of Portsmouth, told CNN that this latest development represents huge progress towards using enzymes to recycle plastic and reduce plastic pollution.
This discovery didn’t happen overnight. In 2016, after spending five years searching through piles of waste, Japanese researchers discovered a strain of bacteria that had naturally evolved to eat polyethylene terephthalate, the common plastic known as PET or polyester. As Smithsonian.com reported then, the new bacteria could break down PET into much smaller compounds. This 2016 discovery was a natural enzyme.

Plastic-eating-Bacteria

The 2018 discovery was a lucky accident scientists examined more closely the crystal structure of a recently discovered enzyme called PETase, which evolved naturally and was already known to break down and digest plastic made of polyethylene terephthalate (PET). When they introduced a mutation to PETase, they produced a new type of enzyme that can digest plastic more efficiently than the enzyme discovered in 2016.

The 2018 discovery was a mutant enzyme that was even more efficient at breaking down plastic waste, signaling  new progress in the international quest for ways to reduce plastic waste. These scientists from the University of Portsmouth in the UK and the US Department of Energy’s National Renewable Energy Laboratory in the US claim to have engineered an enzyme that eats plastic, specifically that can digest polyethylene terephthalate, or PET, and this next step is also reported in the Smithsonian.

See the app @ earthDECKS.org
Saving Our Oceans from Plastic: articles by Zann Gill



Comments

Comments are closed.