Scientists in Britain and the United States say they have engineered a plastic-eating enzyme that could in future help in the fight against pollution.

The enzyme is able to digest polyethylene terephthalate, or PET - a form of plastic patented in the 1940s and now used in millions of tonnes of plastic bottles. PET plastics can persist for hundreds of years in the environment and currently pollute large areas of land and sea worldwide.

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.

PET plastics can persist for hundreds of years in the environment. Credit:Reuters

Finding that this enzyme was helping a bacteria to break down, or digest, PET plastic, the researchers decided to "tweak" its structure by adding some amino acids, said John McGeehan, a professor at Portsmouth who co-led the work.