PET scrap is converted into vanilla flavouring

Researchers have discovered that a common bacteria can be used in a sustainable way to convert post-consumer plastic into vanilla flavouring.

The process results in “vanillin” which is widely used in the food and cosmetics industries and in herbicides, antifoaming agents and cleaning products. Global demand for vanillin was in excess of 37 000 tonnes in 2018.

To help tackle the 50 million tonnes of PET waste produced worldwide annually, scientists from the University of Edinburgh used lab-engineered E. coli to transform terephthalic acid, a molecule derived from PET, into the high value compound through a series of chemical reactions.

The team also demonstrated how the technique works by converting a used plastic bottle into vanillin by adding the E. coli to the degraded plastic waste. They believe the vanillin produced would be fit for human consumption but further experimental tests are required.

Joanna Sadler, a fellow at the School of Biological Sciences, University of Edinburgh, says: ‘This is the first example of using a biological system to upcycle plastic waste into a valuable industrial chemical and this has very exciting implications for the circular economy. The results from our research have major implications for the field of plastic sustainability and demonstrate the power of synthetic biology to address real-world challenges.’

Dr Stephen Wallace, another of the Edinburgh researchers, adds: ‘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 obtained.’

The study, published in Green Chemistry, lays the foundation for further studies to maximise vanillin production towards industrially relevant levels.