Friday February 22, 2019

Plastics Can Be Eaten By Enzymes And Reduce Pollution

The enzyme is able to digest polyethylene terephthalate

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Packs of flattened polyethylene terephthalate (or PET) bottles are carried into a depot before being pulverized as part of a recycling process at Tokyo PET Bottle Recycle Co. in Tokyo, Aug. 13, 2002. Researchers in Britain and the United States have engineered an enzyme that breaks down such plastics.
Packs of flattened polyethylene terephthalate (or PET) bottles are carried.VOA

Scientists in Britain and the United States say they have engineered a plastic-eating enzyme that could help in the fight against pollution.

The enzyme is able to digest polyethylene terephthalate, or PET — a form of plastic patented in the 1940s and now used in millions of tons of plastic bottles. PET plastics can persist for hundreds of years in the environment and currently pollute large areas of land and sea worldwide.

Researchers from Britain’s University of Portsmouth and the U.S. Department of Energy’s National Renewable Energy Laboratory made the discovery while examining the structure of a natural enzyme thought to have evolved in a waste-recycling center in Japan.

Finding that this enzyme was helping a bacteria to break down, or digest, PET plastic, the researchers decided to “tweak” its structure by adding some amino acids, said John McGeehan, a professor at Portsmouth who co-led the work.

This led to a serendipitous change in the enzyme’s actions — allowing its plastic-eating abilities to work faster.

“We’ve made an improved version of the enzyme better than the natural one already,” McGeehan told Reuters in an interview.

“That’s really exciting because that means that there’s potential to optimize the enzyme even further.”

The team, whose finding was published Monday in the Proceedings of the National Academy of Sciences journal, is now working on improving the enzyme further to see if it could be capable of breaking down PET plastics on an industrial scale.

Plastic pollution
Plastic pollution, Pixabay

“It’s well within the possibility that in the coming years we will see an industrially viable process to turn PET, and potentially other [plastics], back into their original building blocks so that they can be sustainably recycled,” McGeehan said.

‘Strong potential’

Independent scientists not directly involved with the research said it was exciting, but cautioned that the enzyme’s development as a potential solution for pollution was still at an early stage.

“Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms,” said Oliver Jones, a Melbourne University chemistry expert. “There is strong potential to use enzyme technology to help with society’s growing waste problem by breaking down some of the most commonly used plastics.”

Douglas Kell, a professor of bioanalytical science at Manchester University, said further rounds of work “should be expected to improve the enzyme yet further.”

Also read: Ayushmann Khurana speaks against plastic pollution

“All told, this advance brings the goal of sustainably recyclable polymers significantly closer,” he added. (VOA)

Next Story

Researchers Find Synthetic Fibers The Major Contributors of Environmental Pollution

Synthetic fibres are petroleum-based products, unlike natural fibres such as wool, cotton and silk, which are recyclable and biodegradable. 

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Synthetic fibres are petroleum-based products, unlike natural fibres such as wool, cotton and silk, which are recyclable and biodegradable.  Pixabay

Polyester and other synthetic fibres like nylon are major contributors of microplastics pollution in the environment, say researchers and suggest switching to biosynthetic fibres to prevent this.

“These materials, during production, processing and after use, break down and release microfibres that can now be found in everything and everyone,” said Melik Demirel, Professor at the Pennsylvania State University in the US.

Synthetic fibres are petroleum-based products, unlike natural fibres such as wool, cotton and silk, which are recyclable and biodegradable.

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Bacteria that consume plastics do exist. However, they are currently at the academic research phase and will take some time to gain industrial momentum. Pixabay

Mixed fibres that contain both natural and synthetic fibres are difficult or costly to recycle.

In the oceans, pieces of microscopic plastic are consumed by plants and animals and enter the human food chain through harvested fish.

In the study, Demirel suggested few things to prevent this: minimising the use of synthetic fibres and switching to natural fibres such as wool, cotton, silk and linen, even though synthetic fibres are less expensive and natural fibres have other environmental costs, such as water and land-use issues; large scale use of bacteria that could aid in biodegradation of the fibres for reuse; substituting synthetic fibres with biosynthetic fibres, that are both recyclable and biodegradable; and blending synthetic fibres with natural fibres to lend them durability while also allowing the blends to be recycled.

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Polyester and other synthetic fibres like nylon are major contributors of microplastics pollution in the environment, say researchers and suggest switching to biosynthetic fibres to prevent this. Pixabay

Also Read: Patients Going Through Gender-Transition Treatment At A Grater Risk Of Cardiac Diseases

Bacteria that consume plastics do exist. However, they are currently at the academic research phase and will take some time to gain industrial momentum.

The study was presented at the 2019 annual meeting of the American Association for the Advancement of Science in the US. (IANS)