According to a new study, the common bacteria E. coli can be used as a sustainable way to transform post-consumer plastic into vanillin.
Vanillin is the main component of the extracted vanilla beans and gives the characteristic taste and smell to vanilla. This latest transformation could improve the circular economy, which aims to remove waste, keep materials and products in use, and contribute positively to synthetic biology, stated experts.
The global plastic crisis has witnessed an urgent need to devise new techniques to recycle polyethylene terephthalate (PET) — a lightweight yet strong plastic obtained from non-renewable resources, like oil and gas. It is extensively used in food and convenience-sized juice and water packaging.
Every year, about 50 million tons of PET waste is generated, resulting in serious environmental and economic issues. Although PET recycling is feasible, present-day processes tend to create products that continue to play a key role in plastic pollution across the world.
To address this issue, scientists from the University of Edinburgh used lab engineered E. coli to convert terephthalic acid — a molecule obtained from PET — into the highly valuable compound vanillin, through a range of chemical reactions. To demonstrate how this technique works, the researchers converted a waste plastic bottle into vanillin by adding the E. coli bacteria to the decomposed plastic waste.
Vanillin is extensively used in the cosmetics and food industries and is also used in the formulation of antifoaming agents, cleaning products, and herbicides. In 2018, the global demand for the product exceeded 37,000 tons.
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.
Joanna Sadler, Study First Author and BBSRC Discovery Fellow, School of Biological Sciences, University of Edinburgh
“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,” stated Dr. Stephen Wallace, Principle Investigator of the study and UKRI Future Leaders Fellow from the School of Biological Sciences at the University of Edinburgh.
This is a really interesting use of microbial science at the molecular level to improve sustainability and work towards a circular economy. 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.
Dr Ellis Crawford, Publishing Editor, Royal Society of Chemistry
Published in the Green Chemistry journal, the study lays the groundwork for more research to boost the production of vanillin toward required industrial levels.
The study was financially supported by UKRI Future Leaders Fellowship and BBSRC Discovery Fellowship.
Sadler, J C & Wallace, S (2021) Microbial synthesis of vanillin from waste poly(ethylene terephthalate. Green Chemistry. doi.org/10.1039/D1GC00931A.