John McGeehan

John McGeehan is a Scottish research scientist and professor of structural biology. He was director of the Centre for Enzyme Innovation (CEI) at the University of Portsmouth until 2022 and is now a principal scientist at the National Renewable Energy Laboratory (NREL), Colorado, US.

In 2018, McGeehan co-led an international team of scientists who characterized and engineered an enzyme with the ability to breakdown polyethylene terephthalate (PET), the primary material used in the manufacture of single-use plastic bottles and synthetic textiles.^[1] The bacteria that produces this enzyme, Ideonella sakaiensis, was originally discovered and isolated in a recycling plant by a Japanese research group in 2016.^[2]

The team at Portsmouth University, together with researchers at NREL and the University of South Florida, solved the high-resolution structure of the PETase enzyme using X-ray crystallography at the Diamond Light Source^[3] and used the structure to design improved versions of the enzyme. The initial research story was covered widely in the press (The Times,^[4] The Guardian,^[5] and The Economist^[6]) and television media (BBC,^[7] ITV,^[8] CNN,^[9] CBS,^[10] Al Jazeera,^[11] and HBO^[12]), reaching a global audience of over 2 billion people. The published research was highlighted in the Altmetric Top 100 of all published papers in 2018^[13] and 2020.^[14]

Plastics, including PET, while incredibly versatile, are resistant to natural breakdown and represent an increasing source of pollution in the environment. ^[15] Enzymes offer potential routes to breakdown plastics into their original monomers to allow circular recycling.^[16] The team continues to make further improvements to these enzymes through the characterisation of natural bacterial systems followed by protein engineering in the laboratory.^[17][18] Their latest work employs the use of AlphaFold from DeepMind (video) to uncover the 3D structures of alternative PETases, and other enzymes.^[19] A driving force for the team is the use of technoeconomic analysis and life-cycle assessment to guide their research direction, and help understand the economic and environmental impacts of new recycling technologies.^[20] Their current focus is on the development of circular systems and industrially scalable processes that reduce energy use and greenhouse gas emissions, and mitigate environmental pollution.^[21]