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.”
 


Ivory Coast looks to solar vehicles to replace bush taxis

Updated 23 September 2018
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Ivory Coast looks to solar vehicles to replace bush taxis

  • A switch to solar and durables may appear paradoxical in Jacqueville, however, as the area produces the lion’s share of the country’s gas and oil
  • Ivory Coast is targeting an 11-percent share of national consumption for renewables by 2020

JACQUEVILLE, Ivory Coast: Hi-tech, cheap — and quiet. The Ivorian resort of Jacqueville just outside Abidjan is betting on solar-powered three-wheelers as it looks to replace traditional but noisy and dirty bush taxis.
“It’s cheaper and relaxing!” says local trader Sandrine Tetelo, of the Chinese-made “Saloni” or “Antara” tricycles, which could eventually spell the end for old-school “woro-woro” four-wheelers as Jacqueville looks to make itself Ivory Coast’s premier eco city.
The mini-cars, 2.7 meters (8.8 feet) long and two meters high, are covered in solar panels each fitted out with six 12-volt batteries, giving the vehicles a range of 140 kilometers (87 miles).
Returning from a visit to China, the solar cars’ promotor Marc Togbe pitched his plan to mayor Joachim Beugre, who was immediately sold.
“We are used to seeing (typically old and beaten up) bush taxis pollute the atmosphere and the environment. We said to ourselves, if we could only replace them by solar trikes,” said Beugre.
“The adventure started in January with two little cars,” added Togbe, who has created a partnership with local businessman Balla Konate.
“I went to China with a friend,” says Konate, “and afterwards I sent four youngsters to Lome for training with a friend who had spoken to me about the project.”
He wants to extend operations to Odienne and Korhogo, towns in the north, the country’s sunniest region.
“Today, a dozen cars are up and running. We are right in the test phase. More and more people are asking for them,” says Beugre, seeing a chance to kill several birds with one solar stone.
Long isolated, his town, nestled between a laguna and the sea, has flourished in terms of real estate and tourism since the 2015 inauguration of a bridge linking Jacqueville to the mainland and cutting transit time to Abidjan to less than an hour.
For the start of the school year in October, Jacqueville plans to bring on stream a 22-seater “solar coach” designed to help deal with “the thorny issue of pupils’ transport.”
Many schoolchildren typically have to travel tens of kilometers from their home village to urban schools.
So far, the trikes have also provided work for around 20 people including drivers and mechanics.
“We’re on the go from six in the morning and finish around 10 or even midnight, weekends too,” says Philippe Aka Koffi, a 24-year-old who has been working as a driver for five months.
“It’s pleasant for doing your shopping more quickly,” says an impressed passenger, Aholia Guy Landry, after riding in a vehicle which can carry four people, driver included.
A big plus is the 100 CFA francs (0.15 euros/$0.18) price of a trip — half a typical downtown “woro-woro” fare — helping to attract between 500 and 1,000 people a day, according to the town hall and promoter.
A switch to solar and durables may appear paradoxical in Jacqueville, however, as the area produces the lion’s share of the country’s gas and oil.
The wells outside the town produce 235 million cubic feet of gas per day, while several foreign firms run pipelines taking oil and gas across the town to feed the refineries at Abidjan.
But the municipality — total budget 140 million CFA francs — sees none of the profits, an issue which has drawn public ire in the past.
The 50-million-CFA trike project is just one piece in a much larger jigsaw which includes the construction of a new eco city on a 240-hectare site among coconut trees.
“It will not be a city for the rich,” insists Beugre, showing off a blueprint replete with cycle paths and a university.
“All social strata who respect the environment will be able to live there,” he adds.
Yet at national level, such plans are conspicuous by their absence.
Ivory Coast, west African leader in electricity production — 75 percent of which comes from thermal energy and the remainder from hydroelectric dams — is targeting an 11-percent share of national consumption for renewables by 2020.
Even though by September the country had burned through barely one single megawatt of solar energy for this year, Beugre is undaunted.
“Our ecological project will go all the way” and “stand up to the power of oil and gas,” says the cowboy-hatted local politician.
“In years to come, we want to ensure that these solar-power machines become the main means of travel in the area.”