Exclusive: Microbes found near plastic refinery appear to turn material into CO2 and antifreeze

Tom Embury-Dennis
@tomemburyd
9 hours ago.

More than one author contributed.

A student may have found a solution to one of the world’s most urgent environmental crises – breeding bacteria capable of “eating” plastic and potentially breaking it down into harmless by-products.

The microbes degrade polyethylene terephthalate (PET) – one of the world’s most common plastics, used in clothing, drinks bottles and food packaging.

Morgan Vague, who is studying biology at Reed College in Oregon, said the process, if sped up, could play a “big part” of solutions to the planet’s plastic problem, which sees millions of tonnes dumped in landfill and oceans every year.

Around 300 million tonnes of plastic is discarded each year, and only about 10 per cent of it is recycled.

“When I started learning about the statistics about all the plastic waste we have, essentially that told me we have a really serious problem here and we need some way to address it,” Ms Vague told The Independent.

After she began learning about bacterial metabolism and “all the crazy things bacteria can do”, the student decided to find out if there were microbes out there able to degrade “straight-from-the-store” plastic.

She began hunting for microbes adapted to degrade plastic in the soil and water around refineries in her hometown of Houston.

Taking her samples back to college in Portland, Oregon, Ms Vague began testing around 300 strains of bacteria for lipase, a fat-digesting enzyme potentially capable of breaking down plastic and making it palatable for the bacteria.

She identified 20 that produced lipase, and of those three that boasted high levels of the enzyme.

Next she put the three microbes, one of which appears to have been previously undiscovered, on a forced diet of PET she cut from strips of water bottles.

She was stunned to find the bacteria worked to digest the PET.

From an earlier scientific research in March 11th 2016

Newly discovered bacteria can eat plastic bottles.

by Deborah Netburn, Los Angeles Times

A team of Japanese scientists has found a species of bacteria that eats the type of plastic found in most disposable water bottles.

The discovery, published Thursday in the journal Science, could lead to new methods to manage the more than 50 million tons of this particular type of plastic produced globally each year.

The plastic found in water bottles is known as polyethylene terephthalate, or PET. It is also found in polyester clothing, frozen-dinner trays and blister packaging.
“If you walk down the aisle in Wal-Mart you’re seeing a lot of PET,” said Tracy Mincer, who studies plastics in the ocean at the Woods Hole Oceanographic Institution in Massachusetts.
Part of the appeal of PET is that it is lightweight, colorless and strong. However, it has also been notoriously resistant to being broken down by microbes-what experts call “biodegradation.”

Previous studies had found a few species of fungi can grow on PET, but until now, no one had found any microbes that can eat it.

To find the plastic-eating bacterium described in the study, the Japanese research team from Kyoto Institute of Technology and Keio University collected 250 PET-contaminated samples including sediment, soil and wastewater from a plastic bottle recycling site.

Next they screened the microbes living on the samples to see whether any of them were eating the PET and using it to grow. They originally found a consortium of bugs that appeared to break down a PET film, but they eventually discovered that just one of bacteria species was responsible for the PET degradation. They named it Ideonella sakainesis.

Further tests in the lab revealed that it used two enzymes to break down the PET.

After adhering to the PET surface, the bacteria secretes one enzyme onto the PET to generate an intermediate chemical.

That chemical is then taken up by the cell, where another enzyme breaks it down even further, providing the bacteria with carbon and energy to grow.

Could a new plastic-eating bacteria help combat this pollution scourge?
Scientists have discovered a species of bacteria capable of breaking down commonly used PET plastic but remain unsure of its potential applications.

Nature has begun to fight back against the vast piles of filth dumped into its soils, rivers and oceans by evolving a plastic-eating bacteria – the first known to science.

How plastic-eating bacteria actually work – a chemist explains.

Scientists have discovered a new technique that could help create more environmentally friendly recycling

Emily Flashman
Friday 20 April 2018 12:26
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