(ORDO NEWS) — As you have no doubt noticed, plastic pollution is a concern, and scientists are working hard to find ways to use plastic without causing long-term environmental damage.
A new study describes the use of a specially engineered variant of the enzyme that significantly reduces the time it takes to break down plastic components.
We could even use this variant of the enzyme to clean up plastic-contaminated areas, says the team that developed it.
In tests, products made from polyethylene terephthalate (PET) polymer decomposed in a week, and in some cases in 24 hours – products that can take centuries to degrade normally under natural conditions.
“The possibilities for using this advanced recycling process in a variety of industries are endless,” says chemical engineer Hal Alper of the University of Texas at Austin.
“In addition to the obvious recycling industry, it also provides an opportunity for corporations from any sector of the economy to take a leading position in the recycling of their products.”
The team named the enzyme FAST-PETase (functional, active, stable and tolerant PETase). They developed an enzyme based on the natural PETase that allows bacteria to degrade PET plastic, and modified it using machine learning to identify five mutations that would allow it to degrade plastic faster in a variety of environmental conditions.
Once the enzyme variant has done its job of breaking down the plastic into its basic molecular units (depolymerization), the researchers have demonstrated that they can reassemble the plastic (repolymerization) through chemical processes to create new plastic products.
To search for FAST-PETase, 51 different recycled plastic containers, five different polyester fibers, and PET fabrics and water bottles were examined.
In testing all of these products, a variant of the enzyme has proven effective at temperatures below 50 degrees Celsius (122 degrees Fahrenheit).
“If you’re looking at environmental cleanup, you need an enzyme that can work in the environment at ambient temperature,” says Alper. “In this requirement, our technology has a huge advantage in the future.”
PET is used in many types of consumer packaging, from textiles to soda bottles. On its own, it is thought to account for about 12 percent of all global waste. If that number isn’t scary enough, try another one: Globally, less than 10 percent of all plastics have been recycled.
The introduction of FAST-PETase can help to some extent in this. The researchers say it’s relatively cheap, portable, and not too difficult to scale to the industrial scale that would be required.
Currently, the most common methods for recycling plastic are tossing it in a landfill, where it rots very slowly, or incinerating it – which is expensive, consumes a lot of energy and fills the atmosphere with harmful gases. Clearly, alternative strategies are badly needed, and this could be one of them.
“This work really demonstrates the possibilities of bringing together different disciplines, from synthetic biology to chemical engineering to artificial intelligence,” says biochemist Andrew Ellington of the University of Texas at Austin.
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