Story at a glance
- Microbes in every corner of the world are evolving to degrade plastic, according to new research by scientists in Sweden.
- More than 30,000 plastic-eating enzymes were discovered in ocean and soil samples from dozens of countries. They’re capable of degrading 10 types of plastics.
- Nearly 60 percent of the enzymes did not fit into any known enzyme class, leaving the door open for additional research.
Across the globe, microbes in oceans and on land are evolving to degrade plastic, a new study has found.
The study, published in the journal of Microbial Ecology by researchers at Chalmers University of Technology in Sweden, found 30,000 different enzymes capable of degrading 10 types of plastic. It’s the first large-scale study of bacteria’s plastic-degrading potential.
According to the study, microbes have evolved in response to plastic pollution. Globally, production of plastics has accelerated rapidly over the last few decades, increasing from 2 million tons in 1950 to 368 million tons in 2019.
“We found multiple lines of evidence supporting the fact that the global microbiome’s plastic-degrading potential correlates strongly with measurements of environmental plastic pollution – a significant demonstration of how the environment is responding to the pressures we are placing on it,” Aleksej Zelezniak, one of the study’s researchers, told The Guardian.
Roughly 12,000 of the new enzymes were found in samples from the ocean, gathered from 67 locations at three different depths. Higher concentrations of degrading enzymes were consistently found at deeper levels in response to greater plastic pollution there, according to the study.
Soil samples were collected from 169 locations in 38 countries and 11 habitats, and yielded 18,000 plastic-degrading enzymes. Scientists concluded the enzyme count was higher in the soil samples than in the ocean samples because soils contain more plastics with phthalate additives, which the new enzymes attack.
Nearly 60 percent of the enzymes found did not fit into any known enzyme classes, according to the research, creating a need for additional research.
“The next step would be to test the most promising enzyme candidates in the lab to closely investigate their properties and the rate of plastic degradation they can achieve,” Zelezniak said. “From there you could engineer microbial communities with targeted degrading functions for specific polymer types.”
That could mean applying the new enzymes to the biodegradation of industrial plastic waste, reducing the need for production of new plastics.
The first plastic-degrading enzyme was inadvertently created by scientists in 2018 after discovering a plastic eating bug in Japan in 2016. In 2020, that enzyme was refined by scientists to degrade plastic six times faster.
That same year, researchers in Germany developed an enzyme that could break down 1 ton of plastic bottles in just 10 hours.
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