Scientists have figured out a way to transform plastic trash into vanilla flavoring, offering a tasty solution to a growing environmental crisis. Researchers at the University of Edinburgh genetically engineered E. coli bacteria — yes, the stuff that causes food poisoning — to treat polyethylene terephthalate (PET), a common synthetic polymer found in water bottles, polyester clothing, car parts, packaging, electronics and more. Enzymes from the bacteria convert the PET into vanillin, the compound that gives vanilla its yummy smell and taste. ‘The global plastic waste crisis is now recognized as one of the most pressing environmental issues facing our planet, prompting urgent calls for new technologies to enable a circular plastics economy,’ biologists Joanna Sadler and Stephen Wallace wrote in the journal Green Chemistry.
Some 55 million tons of PET gets thrown out each year, so new uses for it ‘would have considerable economic as well as environmental impact,’ the authors said. PET is made of ethylene glycol and terepthalic acid, which bond to create long strands of plastic that are then cut up and melted down to make clothing, wrap and more, according to SyFy Wire. Vanillin is an aldehyde, an organic substance made of carbon, hydrogen and oxygen. It can be distilled naturally from vanilla beans but is more commonly synthesized from fossil fuels because it’s cheaper and they’re more readily available. Terepthalic acid has been converted to vanillic acid before, but never into actual vanillin. Sadler and Wallace theorized it could be done with enzymes from E. coli, which uses oxygen as a catalyst.
Through a five-step process, they converted the terephthalic acid from a plastic bottle into vanillin using enzymes produced by E. coli MG1655 RARE (reduced aromatic aldehyde reduction), a form of the bacteria genetically engineered to be benign. After refining their process, Sadler and Wallace were able to produce an end product that was 79 percent vanillin and safe for human consumption. ‘This work substantiates the philosophy that post-consumer plastic may be viewed not as a waste product, but rather as a carbon resource and feedstock to produce high value and industrially relevant materials and small molecules,’ they said. Their research is particularly useful given the soaring demand for vanillin, expected to surpass 65,000 tons within the next few years, according to the study, at a cost of approximately $734 million.
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