Plastic bottles have been converted into vanilla flavoring using genetically engineered bacteria, the first time a valuable chemical has been brewed from waste plastic.
Upcycling plastic bottles into more lucrative materials could make the recycling process far more attractive and effective.
Currently, plastics lose about 95 percent of their value as a material after a single use. Encouraging better collection and use of such waste is key to tackling the global plastic pollution problem.
Photo: AFP
Researchers have already developed mutant enzymes to break down the polyethylene terephthalate (PET) polymer used for drinks bottles into its basic units, terephthalic acid (TA).
Scientists have now used bacteria to convert TA into vanillin.
Vanillin is used widely in the food and cosmetics industries and is an important bulk chemical used to make pharmaceuticals, cleaning products and herbicides.
Global demand is growing and in 2018 was 37,000 tonnes, far exceeding the supply from natural vanilla beans. About 85 percent of vanillin is currently synthesized from chemicals derived from fossil fuels.
“This is the first example of using a biological system to upcycle plastic waste into a valuable industrial chemical and it has very exciting implications for the circular economy,” said Joanna Sadler, a biotechnology fellow at the University of Edinburgh who conducted the new study.
“Our work challenges the perception of plastic being a problematic waste and instead demonstrates its use as a new carbon resource from which high value products can be made,” said Stephen Wallace, a senior lecturer of biotechnology at the university.
About 1 million plastic bottles are sold every minute around the world and just 14 percent are recycled. Even those bottles that are recycled can only be turned into opaque fibres for clothing or carpets.
The research, published in the journal Green Chemistry, used engineered Escherichia coli bacteria to transform TA into vanillin.
The scientists warmed a microbial broth to 37oC for a day, the same conditions as for brewing beer, Wallace said.
This converted 79 percent of the TA into vanillin.
Next the scientists would tweak the bacteria to increase the conversion rate further, he said.
“We think we can do that pretty quickly. We have an amazing roboticized DNA assembly facility here,” he said.
They will also work on scaling up the process to convert larger amounts of plastic. Other valuable molecules could also be brewed from TA, such as some used in perfumes.
“This is a really interesting use of microbial science to improve sustainability,” said Ellis Crawford, publishing editor at the Royal Society of Chemistry. “Using microbes to turn waste plastics, which are harmful to the environment, into an important commodity is a beautiful demonstration of green chemistry.”
Recent research showed bottles are the second-most common type of plastic pollution in the oceans, after plastic bags. In 2018, scientists accidentally created a mutant enzyme that breaks down plastic bottles, and subsequent work produced a super-enzyme that eats plastic bottles even faster.
CONFRONTATION: The water cannon attack was the second this month on the Philippine supply boat ‘Unaizah May 4,’ after an incident on March 5 The China Coast Guard yesterday morning blocked a Philippine supply vessel and damaged it with water cannons near a reef off the Southeast Asian country, the Philippines said. The Philippine military released video of what it said was a nearly hour-long attack off the Second Thomas Shoal (Renai Shoal, 仁愛暗沙) in the contested South China Sea, where Chinese ships have unleashed water cannons and collided with Philippine vessels in similar standoffs in the past few months. The China Coast Guard and other vessels “once again harassed, blocked, deployed water cannons, and executed dangerous maneuvers” against a routine rotation and resupply mission to
GLOBAL COMBAT AIR PROGRAM: The potential purchasers would be limited to the 15 nations with which Tokyo has signed defense partnership and equipment transfer deals Japan’s Cabinet yesterday approved a plan to sell future next-generation fighter jets that it is developing with the UK and Italy to other nations, in the latest move away from the country’s post-World War II pacifist principles. The contentious decision to allow international arms sales is expected to help secure Japan’s role in the joint fighter jet project, and is part of a move to build up the Japanese arms industry and bolster its role in global security. The Cabinet also endorsed a revision to Japan’s arms equipment and technology transfer guidelines to allow coproduced lethal weapons to be sold to nations
‘POLITICAL EARTHQUAKE’: Leo Varadkar said he was ‘no longer the best person’ to lead the nation and was stepping down for political, as well as personal, reasons Leo Varadkar on Wednesday announced that he was stepping down as Ireland’s prime minister and leader of the Fine Gael party in the governing coalition, citing “personal and political” reasons. Pundits called the surprise move, just 10 weeks before Ireland holds European Parliament and local elections, a “political earthquake.” A general election has to be held within a year. Irish Deputy Prime Minister Micheal Martin, leader of Fianna Fail, the main coalition partner, said Varadkar’s announcement was “unexpected,” but added that he expected the government to run its full term. An emotional Varadkar, who is in his second stint as prime minister and at
Thousands of devotees, some in a state of trance, gathered at a Buddhist temple on the outskirts of Bangkok renowned for sacred tattoos known as Sak Yant, paying their respects to a revered monk who mastered the practice and seeking purification. The gathering at Wat Bang Phra Buddhist temple is part of a Thai Wai Khru ritual in which devotees pay homage to Luang Phor Pern, the temple’s formal abbot, who died in 2002. He had a reputation for refining and popularizing the temple’s Sak Yant tattoo style. The idea that tattoos confer magical powers has existed in many parts of Asia