An inadvertently-engineered creation discovered by U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the United Kingdom’s University of Portsmouth has caused a breakthrough in PETase, offering a vital solution to plastic pollution.
Ideonella sakaiensis, also known as PETase (PET-digesting enzyme), was first discovered in 2016 by Yoshida et al, who found the bacterium living in the soil at a recycling plant in Japan that was piled with used bottles. This bacterium was unique as it could use Polyethylene terephthalate (PET) as its major carbon and energy source. This means that these bacteria can simply feed on plastic used to make disposable beverage bottles for survival and growth.
With this discovery, U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the United Kingdom’s University of Portsmouth dedicated a research team to determine the enzymes structure. While researching, the team inadvertently created a mutant PETase. “We hoped to determine its structure to aid in protein engineering, but we ended up going a step further and accidentally engineered an enzyme with improved performance at breaking down these plastics.” explained the research team in NREL’s statement.
It is estimated that a staggering 9 billion ton of plastics can be found on our planet ever since large scale plastic manufacturing came about in the 1950s. Within less than a century, plastic has become an indispensable product in modern civilisation due to its multifaceted properties. Plastics are complex polymers (strong, repeating chains of molecules that requires a long time to be broken down) that pose a severe threat to the environment and especially, the marine ecosystems.
As compared to the original enzyme, the mutant’s appetite has dramatically increased and the process of feeding has accelerated. Not only is this new creation more effective than PETase, the differentiating feature lies in its ability to consume another type of plastic, Polyethylene furandicarboxylate (PEF). “It is literally drilling holes through the PEF sample. This shows that by using PETase, PEF is even more biodegradable than PET,” said NREL’s Gregg Beckham, one of the leading researchers. This new creation opens a new door to offer a solution to the deteriorating ecosystem.
Although it is said that the mutant PETase is only around 20% more efficient than the original PETase, the main takeaway is that these enzymes are able to be optimised and enhance.
In other words, if scientists and researchers carry on their explorations and research, future engineered enzymes may be better at breaking down these plastics and would be able to break down other environmentally damaging materials as well.
Of course, time is of the essence and it would take a while before these creations can be able to break down the 9 billion of tonnes of plastic.
Now, with a proof of concept, we are able to use science to clear up the “trash” that we have fed earth with at a quicker pace. In the meantime, we can all do our part to help minimise the damage – small things such as using our own water bottles instead of buying disposable ones. “We can all play a significant part in dealing with the plastic problem. But the scientific community who ultimately created these ‘wonder-materials,’ must now use all the technology at their disposal to develop real solutions,” says University of Portsmouth’s John McGeehan in the same statement by NREL.