Bugs across globe are evolving to eat plastic, study finds

Microbes in oceans and soils across the globe are evolving to eat plastic, according to a study.

The research scanned more than 200m genes found in DNA samples taken from the environment and found 30,000 different enzymes that could degrade 10 different types of plastic.

The study is the first large-scale global assessment of the plastic-degrading potential of bacteria and found that one in four of the organisms analysed carried a suitable enzyme. The researchers found that the number and type of enzymes they discovered matched the amount and type of plastic pollution in different locations.

Millions of tonnes of plastic are dumped in the environment every year, and the pollution now pervades the planet, from the summit of Mount Everest to the deepest oceans. Reducing the amount of plastic used is vital, as is the proper collection and treatment of waste.

But many plastics are currently hard to degrade and recycle. Using enzymes to rapidly break down plastics into their building blocks would enable new products to be made from old ones, cutting the need for virgin plastic production. The new research provides many new enzymes to be investigated and adapted for industrial use.

The explosion of plastic production in the past 70 years, from 2m tonnes to 380m tonnes a year, had given microbes time to evolve to deal with plastic, the researchers said. The study, published in the journal Microbial Ecology, started by compiling a dataset of 95 microbial enzymes already known to degrade plastic, often found in bacteria in rubbish dumps and similar places rife with plastic.

The team then looked for similar enzymes in environmental DNA samples taken by other researchers from 236 different locations around the world. Importantly, the researchers ruled out potential false positives by comparing the enzymes initially identified with enzymes from the human gut, which is not known to have any plastic-degrading enzymes.