Speaking before a meeting of the Commonwealth heads of government in London, the prime minister said: "This week we will look closely at how we can tackle the many threats to the health of the world's oceans, including the scourge of marine plastic pollution".
"The engineering process is much the same as for enzymes now being used in bio-washing detergents and in the manufacture of biofuels", said McGeehan. "It is incredibly resistant to degradation". "It is so easy for manufacturers to generate more of that stuff, rather than even try to recycle". There have been clear and regular indications in recent months that government bodies are working towards the development of a circular plastics economy - a model which the modified enzyme could potentially help to establish.
The researchers' goal was to understand how one of its enzymes - called PETase - worked, by figuring out its structure.
The team set out to determine how the enzyme evolved and if it might be possible to improve it.
The researchers worked with scientists at Diamond Light Source (DLS) in the United Kingdom, deploying a synchrotron that uses intense beams of X-rays 10 billion times brighter than the sun to act as a microscope powerful enough to see individual atoms.More news: Kashmir lawyers protest against supporters of Kathua rape accused
"It is a modest improvement - 20 percent better - but that is not the point", said McGeehan. "It's incredible because it tells us that the enzyme is not yet optimised".
Industrial enzymes are widely used in, for example, washing powders and biofuel production, They have been made to work up to 1,000 times faster in a few years, the same timescale McGeehan envisages for the plastic-eating enzyme.
Researchers from Britain's University of Portsmouth and the US Department of Energy's National Renewable Energy Laboratory made the discovery while examining the structure of a natural enzyme thought to have evolved in a waste recycling centre in Japan.
The mutant enzyme can also degrade polyethylene furandicarboxylate, or PEF, a bio-based substitute for PET plastics that is being hailed as a replacement for glass beer bottles.
The cash will be used for grants, innovation challenges and events to raise the profile of the plastic problem and fund the development of alternative materials and new, zero-waste manufacturing processes.More news: ATMs across country go dry, Arun Jaitley says 'temporary shortage'
"Other types of plastic could be broken down by bacteria currently evolving in the environment, McGeehan said: "People are now searching vigorously for those".
"Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms", said Oliver Jones, a Melbourne University chemistry expert.
That leaves £16.4m which will be spent on improving waste management at a national and city level to stop plastics entering the water.
Scientists in Britain and the U.S. have engineered a plastic-eating enzyme that could in future help in the fight against pollution. "[But] this is certainly a step in a positive direction".More news: Alfie Evans' parents lose legal bid in attempt to save son