Scientists in Germany have identified plastic-eating fungi that could offer a glimmer of hope in tackling the problem of millions of tonnes of waste polluting the world's oceans every year.
But they warn that their work is likely to be only a small part of solving plastic pollution, and say there is still a need to reduce food packaging and other debris from entering the environment where it can take decades to degrade.
An analysis at Lake Stechlin in north-eastern Germany into how microfungi thrive on some plastics with no other carbon source to feed on has clearly demonstrated that some of them are capable of degrading synthetic polymers, said the team leader.
"The most surprising finding of our work ... is that our fungi could exclusively grow on some of the synthetic polymers and even form biomass," Hans-Peter Grossart, head of the research group at the Leibniz Institute of freshwater Ecology and Inland Fisheries, told Reuters TV.
Grossart believes the microbial plastic destroyers could be used in sewage treatment plants or other facilities with controlled conditions. However, the fungi are unlikely to be a solution for stemming the global flood of waste.
"We should definitely try to release as little plastic as possible into the environment," Grossart told Reuters. "Plastic is made from fossil carbon and if the mushrooms break it down, it's no different to us burning oil or gas and releasing CO2 into the atmosphere.
Of 18 selected fungal strains, four proved to be particularly "hungry", which means they could efficiently utilise plastics, especially polyurethane which is used to make construction foam.
Polyethylene, used in plastic bags and packaging, was much slower to degrade, and microplastics from tyre abrasion were the most difficult, largely because of additives like heavy metals.
Grossart said he believes the fungi's ability to utilise plastic is an adaptation to the vast amounts of plastic carbon in the environment.
However, their enzyme activity is heavily dependent on external conditions, such as temperature or micronutrients.
Some 390 million tonnes of plastic were produced worldwide in 2021, data from the Plastics Europe plastics producer association show, up from 1.7 million tonnes in 1950. Although the recycling rate has increased in the last few years, less than 10% of plastic waste is recycled worldwide.
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