Plastic bottles have been made into vanilla flavoring using genetically modified bacteria, the first time a valuable chemical has been made from plastic waste.
Recycling plastic bottles into more lucrative materials could make the recycling process much more attractive and effective. Currently, plastics lose around 95% of their value as a material after just one use. Promoting better collection and use of such waste is key to tackling the global problem of plastic pollution.
Researchers have already developed mutant enzymes to break down the polyethylene terephthalate polymer used for beverage bottles into its basic units, terephthalic acid (TA). Scientists have now used insects to convert TA to vanillin.
Vanillin is widely used in the food and cosmetic industries and is an important bulk chemical used to make pharmaceuticals, cleaning products, and herbicides. World demand is growing and in 2018 it was 37,000 tons, far exceeding the supply of natural vanilla. Approximately 85% of vanillin is currently synthesized from chemicals derived from fossil fuels.
Joanna Sadler from the University of Edinburgh, who carried out the new work, said: “This is the first example of using a biological system to recycle plastic waste into a valuable industrial chemical and it has very interesting implications for the circular economy.”
Stephen Wallace, also from the University of Edinburgh, said: “Our work challenges the perception that plastic is a problematic waste and instead demonstrates its use as a new carbon resource from which high-quality products can be made. value”.
Approximately 1 million plastic bottles are sold every minute worldwide and only 14% are recycled. Currently even those bottles that are recycled can only be turned into opaque fibers for clothing or carpets.
The investigation, published in Green Chemistry magazine, used E. coli bacteria designed to transform TA into vanillin. The scientists heated a microbial broth to 37 ° C for one day, the same conditions as for brewing, Wallace said. This converted 79% of the TA to vanillin.
The scientists will then further modify the bacteria to further increase the conversion rate, he said: “We think we can do that pretty quickly. We have an amazing robotic DNA assembly facility here. “They will also be working on scaling up the process to convert large amounts of plastic. Other valuable molecules could also be made from TA, like some used in perfumes.
Ellis Crawford from the Royal Society of Chemistry said: “This is a really interesting use of microbial science to improve sustainability. Using microbes to turn environmentally harmful waste plastics into an important product is a beautiful demonstration of green chemistry. “
Recent research showed that 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 superzyme that eats away plastic bottles even faster.
George is Digismak’s reported cum editor with 13 years of experience in Journalism