Cold-loving plastic-digesting microbes could tackle plastic pollution

Researchers have discovered microorganisms that can digest plastic in cold temperatures

Spotted: Residues of plastic have been found in every corner of the world, so it makes sense that there may also be microbes that can break down plastic in places like the Alps and the Arctic. This is what microbiologists Joel Rüthi and Beat Frey from the Swiss Federal Institute for Forest, Snow, and Landscape Research WSL set out to investigate.

The team buried plastic in soil samples taken from 3,000 metres above sea level in the Swiss Alps, including two types of biodegradable plastic used for compost bags and polyethylene (PE). After five months at 15 degrees Celsius (59 degrees Fahrenheit), the compostable plastic had been partially broken down. The polyethylene, however, was unchanged.

Rüthi then sequenced the DNA of the growth on the compostable plastic. The team found numerous strains of fungi and bacteria, as well as genes for enzymes that can break down the long molecule chains of the compostable plastic. None of the strains, however, could digest the PE, even after 126 days spent on the plastic.

The researchers concluded that even at low temperatures and high altitudes, there are bacteria present capable of using the plastic as a source of energy and carbon. One long-term goal is to find enzymes that can break down plastic into its constituent building blocks and then use these to produce new plastics. “This would make a real circular economy for plastic possible,” says Rüthi.

The world now produces almost 400 million tonnes of plastic every year, most of it from fossil fuels. Plastic pollution has become one of the most pressing environmental concerns. Luckily, Springwise is spotting a wide range of innovations that aim to tackle this scourge. These range from stronger paper bags that could replace plastic to a process for manufacturing polyester out of waste CO2.

Written By: Lisa Magloff