Researchers accidentally engineer plastic-eating enzyme

A boy stands near a whale-shaped art installation that is made of plastic and trash made by environmental activist group Greenpeace Philippines, lying along the shore in Naic, Cavite in the Philippines, in this May 12, 2017 file photo. (REUTERS)
Updated 17 April 2018
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Researchers accidentally engineer plastic-eating enzyme

  • Despite recycling efforts, most plastic can persist for hundreds of years in the environment
  • Researchers say they are now working on further improvements to the enzyme

TAMPA: Researchers in the US and Britain have accidentally engineered an enzyme which eats plastic and may eventually help solve the growing problem of plastic pollution, a study said Monday.
More than eight million tons of plastic are dumped into the world’s oceans every year, and concern is mounting over this petroleum-derived product’s toxic legacy on human health and the environment.
Despite recycling efforts, most plastic can persist for hundreds of years in the environment, so researchers are searching for better ways to eliminate it.
Scientists at the University of Portsmouth and the US Energy Department’s National Renewable Energy Laboratory decided to focus on a naturally occurring bacterium discovered in Japan a few years ago.
Japanese researchers believe the bacterium evolved fairly recently in a waste recycling center, since plastics were not invented until the 1940s.
Known as Ideonella sakaiensis, it appears to feed exclusively on a type of plastic known as polyethylene terephthalate (PET), used widely in plastic bottles.

The researchers’ goal was to understand how one of its enzymes — called PETase — worked, by figuring out its structure.
“But they ended up going a step further and accidentally engineered an enzyme which was even better at breaking down PET plastics,” said the report in the Proceedings of the National Academy of Sciences, a peer-reviewed US journal.
Using a super-powerful X-ray, 10 billion times brighter than the Sun, they were able to make an ultra-high-resolution three-dimensional model of the enzyme.
Scientists from the University of South Florida and the University of Campinas in Brazil did computer modeling which showed PETase looked similar to another enzyme, cutinase, found in fungus and bacteria.
One area of the PETase was a bit different, though, and researchers hypothesized that this was the part that allowed it to degrade man-made plastic.
So they mutated the PETase active site to make it more like cutinase, and unexpectedly found that this mutant enzyme was even better than the natural PETase at breaking down PET.
Researchers say they are now working on further improvements to the enzyme, with the hope of eventually scaling it up for industrial use in breaking down plastics.
“Serendipity often plays a significant role in fundamental scientific research, and our discovery here is no exception,” said study author John McGeehan, professor in the School of Biological Sciences at Portsmouth.
“Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics.”
 


Japan to trial ‘world’s first urine test’ to spot cancer

Updated 17 April 2018
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Japan to trial ‘world’s first urine test’ to spot cancer

  • Previous research has shown a new blood test has potential to detect eight different kinds of tumors before they spread
  • The research starts in April and will run until September

TOKYO: A Japanese firm is poised to carry out what it hailed as the world’s first experiment to test for cancer using urine samples, which would greatly facilitate screening for the deadly disease.
Engineering and IT conglomerate Hitachi developed the basic technology to detect breast or colon cancer from urine samples two years ago.
It will now begin testing the method using some 250 urine samples, to see if samples at room temperature are suitable for analysis, Hitachi spokesman Chiharu Odaira told AFP.
“If this method is put to practical use, it will be a lot easier for people to get a cancer test, as there will be no need to go to a medical organization for a blood test,” he said.
It is also intended to be used to detect paediatric cancers.
“That will be especially beneficial in testing for small children” who are often afraid of needles, added Odaira.
Research published earlier this year demonstrated that a new blood test has shown promise toward detecting eight different kinds of tumors before they spread elsewhere in the body.
Usual diagnostic methods for breast cancer consist of a mammogram followed by a biopsy if a risk is detected.
For colon cancer, screening is generally conducted via a stool test and a colonoscopy for patients at high risk.
The Hitachi technology centers around detecting waste materials inside urine samples that act as a “biomarker” — a naturally occurring substance by which a particular disease can be identified, the company said in a statement.
The procedure aims to improve the early detection of cancer, saving lives and reducing the medical and social cost to the country, Odaira explained.
The experiment will start this month until through September in cooperation with Nagoya University in central Japan.
“We aim to put the technology in use in the 2020s, although this depends on various things such as getting approval from the authorities,” Odaira said.