Using genetically engineered bacteria, plastic bottles have been converted into vanilla flavoring. It is the 1st time a valuable chemical has been made from waste plastics. Plastics being upcycled into more lucrative materials could make the recycling process far more effective after single-use plastics lose about 95% of their value as a material. The use of such waste and encouraging better collection and is a critical way to tackle global plastic pollution.
Mutant enzymes to break down the polyethylene terephthalate polymer used for drinks bottles have already been developed by researchers into its basic unit, terephthalic acid. Scientists are using bugs to convert terephthalic acid into vanillin. It is widely used in the cosmetics and food industry and is a critical bulk chemical used to make herbicides, cleaning products, pharmaceuticals. The global demand for the product is increasing. From chemicals derived from fossil fuels, about 85% of vanillin is currently synthesized.
Joanna Sadler, of the University of Edinburgh, who conducted the new work, said: “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.”
Stephen Wallace, also of the University of Edinburgh, said: “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.”
Around the world, 1m of plastic bottles are sold every minute, and just 14% are recycled. Currently, those bottles that are recycled can only be turned into opaque fibers for carpets and clothing. Ecoil bacteria were used by the research published in the journal Green Chemistry to transform terephthalic acid into vanillin. Wallace said the scientist warmed a microbial broth to 37C for a day, the same conditions as for brewing beer. This converts 79% terephthalic acid into vanillin.
He said, to increase the conversion rate further next, the scientists will further tweak the bacteria. Scientists think that they do that pretty quickly. There is a fantastic robotized DNA assembly facility there. The work on scaling up the process to convert more significant amounts of plastic is done by them. Other valuable molecules could also be obtained from terephthalic acids, such as some used in perfumes.