Scientists Turn Plastic Waste Into Parkinson’s Drug Levodopa Using Engineered Bacteria

A caller engineered microbial strategy transforms discarded integrative into a frontline Parkinson’s treatment, offering a glimpse into a early wherever discarded becomes medicine.

Study: Microbial upcycling of integrative discarded to levodopa. Image Credit: jmcatholic / Shutterstock

In a caller study published successful nan journal Nature Sustainability, researchers show nan successful engineering of a biologic process to "upcycle" poly(ethylene terephthalate) (PET) into levodopa (L-DOPA), a frontline medicine for Parkinson's illness (PD). The researchers modified Escherichia coli to person plastic-derived monomers into high-value pharmaceuticals nether mild, aqueous conditions.

The study overcame important biochemical hurdles involving cellular carrier and enzyme inhibition by separating nan process crossed 2 cooperative microbial strains. The findings revealed a precocious accumulation titre of 5.0 g L-1 successful an optimized two-step preparative system. This attack offers a perchance much sustainable way than accepted fossil fuel-derived chemic aliases chemoenzymatic synthesis, though it remains a proof-of-concept alternatively than a afloat optimized business process.

Plastic Waste Crisis and Sustainable Chemistry Challenges

The modern chemic industry, peculiarly pharmaceuticals, is built connected a instauration of finite fossil resources, a exemplary that, contempt redeeming millions of lives, is inherently unsustainable and environmentally damaging. At nan aforesaid time, nan biosphere is nether expanding accent from nan world accumulation and accumulation of plastics derived chiefly from fossil fuels.

Environmental reports bespeak that complete 400 cardinal metric tons of integrative are produced annually, of which astir 360 cardinal tons extremity up arsenic waste. The mostly of this discarded is sent to landfills aliases incinerated, resulting successful nan nonaccomplishment of valuable c and important greenhouse state emissions. While accepted recycling exists, researchers progressively attraction connected "upcycling", converting discarded into higher-value products, arsenic a much sustainable pathway toward a information economy.

Levodopa (L-DOPA) is simply a wide utilized therapy for Parkinson's disease. Its commercialized accumulation typically relies connected fossil fuel-derived chemic aliases chemoenzymatic synthesis, which often involves harsh conditions and generates important waste.

Although biologic accumulation of L-DOPA from glucose aliases amino acids has been explored, these approaches often show debased ratio and look challenges for business scalability.

Approaches to nan recycling, upcycling and biology disposal of PET integrative waste, including nan projected bio-upcycling of PET discarded to nan Parkinson’s medication l-DOPA successful engineered bacteria. a, Current: closed-loop recycling. b, This work: microbial upcycling. Credit: photographs in a, Rawpixel (https://www.rawpixel.com); bacterial icon in b, Bioicons (https://bioicons.com).

Engineered E. coli Pathway for Plastic Conversion

The study aimed to flooded these limitations by leveraging bioengineering strategies to person integrative discarded into a analyzable therapeutic product. The attack focused connected terephthalic acerb (TPA), a monomer derived from PET degradation.

The researchers designed a de novo four-step biosynthetic pathway involving 7 genes, which were introduced into Escherichia coli BL21(DE3). Initial testing revealed 2 awesome bottlenecks.

First, nan germs struggled to carrier TPA crossed compartment membranes astatine neutral pH. This was addressed by expressing nan transporter macromolecule TpaK from Rhodococcus jostii, which importantly improved uptake.

Second, a pathway intermediate, protocatechuate (PCA), inhibited nan last enzyme, tyrosine-phenol lyase (TPL), done feedback inhibition. In vitro experiments showed that PCA concentrations supra 2 mM eliminated detectable L-DOPA production, while whole-cell systems showed a driblet successful conversion ratio from 80% to 0% supra 1 mM PCA.

This situation was flooded by splitting nan pathway betwixt 2 microbial strains. One strain converts TPA into catechol, while nan 2nd converts catechol into L-DOPA.

The strategy was besides tested utilizing real-world waste, including business hot-stamping foils (HSF) and post-consumer integrative bottles. Additionally, nan microalga Chlamydomonas reinhardtii was utilized to seizure c dioxide (CO2) generated during nan process, supporting a proof-of-concept carbon-neutral accumulation cycle.

Experimental Results and Production Efficiency Metrics

The engineered strategy achieved a L-DOPA titre of 5.0 g L-1, corresponding to an 84% conversion ratio from business discarded successful an optimized two-step workflow utilizing foil-derived TPA. The summation of nan TpaK transporter importantly improved TPA-to-PCA conversion astatine neutral pH.

Incorporating C. reinhardtii reduced CO2 levels successful nan civilization headspace to undetectable levels wrong 12 hours, demonstrating nan integration of metabolic by-products into biomass nether experimental conditions.

Using TPA derived from a discarded PET vessel resulted successful a 49% conversion rate. In abstracted experiments pinch foil-derived TPA, nan process yielded 193 mg of L-DOPA arsenic a coagulated salt, corresponding to respective objective doses for early-stage Parkinson's disease.

Implications for Sustainable Pharma and Limitations

This study provides a proof-of-concept that integrative discarded tin beryllium converted into valuable pharmaceutical compounds, highlighting a imaginable strategy to reside some biology contamination and sustainable supplier production.

However, further optimization is required earlier business application. Key areas see nonstop precipitation of L-DOPA from fermentation broth, removal of residual contaminants from integrative discarded streams, genomic integration of pathway genes to destruct nan request for antibiotic selection, and further improvement of algal CO2 seizure systems.