Transform post-consumer plastic into vanillin
Vanilla is perhaps the world’s most popular flavor, but less than 1% of it comes from a fully natural source, the vanilla orchid. In 2015, a host of big food brands, led by Nestlé, vowed to use only natural flavors in products marketed in the U.S.—just as a shortage of natural vanilla was emerging. In the following pages, C&EN explains how flavor firms are working to supply natural alternatives that can help satisfy consumers’ cravings for vanilla. In an effort to shore up vanilla supplies, these same companies are working with orchid growers in Madagascar to ensure the future of sustainable, high-quality vanilla production.
Poly(ethylene terephthalate) (PET) is an abundant and extremely useful material, with widespread applications across society.
However, there is an urgent need to develop technologies to valorise post-consumer PET waste to tackle plastic pollution and move towards a circular economy.
Whilst PET degradation and recycling technologies have been reported, examples focus on repurposing the resultant monomers to produce more PET or other second-generation materials. Herein, we report a novel pathway in engineered Escherichia coli for the direct upcycling of PET derived monomer terephthalic acid into the value-added small molecule vanillin, a flavour compound ubiquitous in the food and cosmetic industries, and an important bulk chemical. After process optimisation, 79% conversion to vanillin from TA was achieved, a 157-fold improvement over our initial conditions.
Parameters such as temperature, cell permeabilisation and in situ product removal were key to maximising vanillin titres. Finally, we demonstrate the conversion of post-consumer PET from a plastic bottle into vanillin by coupling the pathway with enzyme-catalysed PET hydrolysis. This work demonstrates the first biological upcycling of post-consumer plastic waste into vanillin using an engineered microorganism.
The Royal Society of Chemistry 2021
Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh