Researchers have developed a biotechnological process that converts polyethylene terephthalate (PET) plastic waste into levodopa (L-DOPA) – the key drug for treating Parkinson's disease. The approach uses genetically modified Escherichia coli and achieves high yields under mild, aqueous conditions.
The team led by Benjamin Royer and Stephen Wallace constructed a four-step biosynthetic pathway that converts terephthalic acid (TPA) – the main monomer of PET – to L-DOPA via protocatechuate and catechol. Two key bottlenecks – substrate import and feedback inhibition by protocatechuate – were overcome by expressing a TPA transporter (TpaK) from Rhodococcus jostii and separating the pathway into two strains (one for TPA to catechol, the other for catechol to L-DOPA).
In an optimized two-strain process, 5,0 g/l of L-DOPA was obtained from 5 mM TPA. The process was successfully applied to industrial PET waste and a single used plastic bottle; preparative amounts of L-DOPA salt were isolated.
To further improve sustainability, CO? released from the decarboxylation of TPA was captured by the microalga Chlamydomonas reinhardtii – a proof-of-concept for CO? recycling in the process.
This work demonstrates how engineering biology can transform plastic waste into high-value pharmaceuticals and offers an alternative to fossil-based synthesis pathways for L-DOPA. Current production (~250 t/year) is based on petrochemical or chemoenzymatic methods, which face challenges in terms of carbon efficiency and sustainability.
Source:
Nature Sustainability, “Microbial upcycling of plastic waste to levodopa”, by Benjamin Royer, Yuta Era et al. (Stephen Wallace as corresponding author), published on March 16, 2026
DOI: 10.1038/s41893-026-01514-0 (Open Access)
https://www.nature.com/articles/s41893-026-01514-0
