About the Project
An estimated 31.9 million tonnes of mismanaged plastic waste enters the environment annually,[1] contaminating oceans and terrestrial ecosystems. This poses a severe threat to the environment and wildlife, and also results in the loss of a valuable carbon source. While some plastics can be mechanically recycled, this rapidly diminishes the material properties until the recyclate is no longer useful. Chemical recycling to monomer is therefore emerging as an important complementary technique,…
where the monomer can be re-polymerised into materials with properties comparable to virgin plastics.
The use of biotechnology solutions to depolymerise plastic waste is a growing area of interest, with lipases, cutinases and PETases reported for poly(ethylene terephthalate) (PET) depolymerisation.[2] While most enzymes can only depolymerise amorphous PET, exciting recent advances suggest that enzymes can depolymerise crystalline PET under certain conditions.[3] This is a key finding, as incomplete depolymerisation can generate damaging microplastics. In contrast, most metal-based catalysts can depolymerise both amorphous and crystalline regions of PET, yet generally use harsh reaction conditions. Due to stability issues, this limits the use of ligands designed to enhance catalyst activity, although recent studies have shown that heterobimetallic catalysts can effectively depolymerise polyesters.[4]
This collaborative project harnesses the power of both enzymes and metal-based catalysts, by incorporating metal-salen complexes into artificial metalloenzymes designed to stabilise the metal-salen and direct the polymer towards the active site. The catalysts will be explored for polyester depolymerisation, specifically investigating poly(lactic acid) (PLA) and poly(ethylene furanoate) (PEF). These two materials are emerging as next-generation green polyesters; both are bio-based, non-toxic, and generate lower CO2 emissions than some conventional plastics.[5] Several studies, including our own research, have shown that salen complexes can be successfully incorporated into artificial metalloenzymes to deliver enhanced catalyst performance, yet the use of artificial metalloenzymes remains underexplored in depolymerisation.[6] The catalysts will be optimised by modulating the salen structure, including the use of chiral salens for depolymerising PLA of different tacticity.
This project would suit a student interested in sustainability and interdisciplinary research, and training will be provided in molecular biology, synthetic chemistry and analysis.
How to Apply
Closing date is Monday 16th November 2026, 11.59 pm GMT.
This 4-year PhD project is part of a competition funded by EastBio Partnership. For detailed guidance on the application process and the EastBio Application and Reference Forms, please see: https://biology.ed.ac.uk/eastbio/how-to-apply
Please send your completed EastBio Application Form and a copy of your academic transcripts in pdf format to the Lead Supervisor, email: J.Garden@ed.ac.uk
Please also contact your referees and ask them to submit their references on the EastBio reference form template to the hiring supervisor: email J.Garden@ed.ac.uk before the application deadline of 16th November 2026.
Funding Notes
This 48 month fully funded opportunity is open to UK and international students and provides funding covering stipend and UK level tuition fees. The University of Edinburgh covers the difference between home and international fees meaning that the EastBio Partnership offers fully-funded studentships to all appointees. There is a cap on the number of international students the DTP recruits. It is therefore important for us to know from the outset which fees status category applicants will fall under when applying to the University (see section 2 ‘EastBio (UKRI) funding eligibility’ of the EastBio application form).
References
- Rochman, Science, 2018, 360(6384), 28
- Niu et al., Chem. Sci., 2024, 15, 6200
- Auclair et al., Proc. Nat. Acad. Sci, 2021, 118(29), e2026452118
- Garden et al., J. Am. Chem. Soc, 2025, 147(40), 36697
- Varrone et al., ACS Sustain. Chem. Eng., 2024, 12(26), 9658
- Lu et al., Proc. Nat. Acad. Sci., 2023, 120(43), e2308286120