Scientists have developed a novel way to use plastic waste as a food industry resource by converting post-consumer PET into vanillin via a series of chemical reactions. 

The team from the University of Edinburgh, UK, lab-engineered E. coli to transform terephthalic acid – a molecule derived from PET – into the molecule known for giving vanilla its characteristic taste and smell. Scientists demonstrated the technique by converting a used plastic bottle into vanillin.

"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," says Dr. Stephen Wallace, principal investigator of the study and UK Research and Innovation (UKRI) Future Leaders Fellow from the University of Edinburgh. 

Researchers say that the vanillin produced would be fit for human consumption, but further experimental tests are required. 

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

Microbes to boost sustainability 
The study is the first example of using a biological system to upcycle plastic waste into a valuable industrial chemical, explains Joanna Sadler, first author and Biotechnology and Biological Sciences Research Council (BBSRC) Discovery Fellow from the School of Biological Sciences, University of Edinburgh. 

The worlds plastic crisis has seen an urgent need to develop new methods to recycle PET – the strong, lightweight plastic derived from non-renewable materials such as oil and gas and widely used for packaging foods and convenience-sized juices and water.

Approximately 50 million metric tons of PET waste are produced annually, causing serious economic and environmental impacts. PET recycling is possible, but existing processes create products that continue to contribute to plastic pollution worldwide.

"This is a really interesting use of microbial science at the molecular level to improve sustainability and work toward a circular economy," affirms Dr. 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 and platform molecule with broad applications in cosmetics and food is a beautiful demonstration of green chemistry."

Edible packaging is another way the food industry is fighting the plastic problem, with packaging solutions sourced from seaweed or casein.

Queen of flavors 
Known as the "Queen of Flavors," vanilla is the second most sought-after flavor in food and beverages after mint. The classic and versatile taste continues to be a platform for taste combinations and new F&B applications. 

Last year, Innova Market Insights reported that new vanilla-flavored products increased by 24 percent over the previous five years. Moreover, the Edinburgh-based researchers report that global demand for vanillin was in excess of 37,000 metric tons in 2018. 

Currently, vanillin can be produced from both natural and synthetic sources, with most vanillin to date coming from synthetic sources. 

Vanillin derived from its conventional vanilla bean source also continues to see interest from industry as consumers seek food and beverages with premium, natural and ethical positioning.