In total, more than 30,000 enzymes were found with the potential to break down 10 different types of commonly used plastic.
Plastic production has exploded in the last seventy years. That has been enough time for various microbes to respond to this ‘attack’, evolving to degrade this type of compound: scientists from Chalmers University (Sweden) have analyzed hundreds of DNA samples from the environment taken around the world and have found 30,000 different enzymes capable of breaking down up to 10 different types of plastic. The results of this research have just been published in the journal ‘ bio ‘.
The team used computer models to search for microbial enzymes with the potential to degrade plastic, which was then compared to official figures for plastic waste pollution in countries and oceans. “Our data demonstrates that the global microbiome’s plastic degradation potential correlates strongly with measurements of environmental plastic pollution, a significant demonstration of how the environment is responding to the pressures we are putting on it,” Aleksej said in a statement. Zeleznik, Associate Professor of Systems Biology at Chalmers.
In other words, the quantity and diversity of enzymes that degrade plastic are increasing in direct response to local levels of contamination of this material. Some of the locations that contained the highest amounts of diversity and number of enzymes were the ones with the most debris, such as samples taken from the Mediterranean Sea and the South Pacific Ocean.
“Currently, very little is known about these plastic-degrading enzymes, and we did not expect to find such a large number of them in so many different microbes and environmental habitats. This is a surprising discovery that really illustrates the magnitude of the problem”, says Jan Zrimec, first author of the study, collaborator Zelezniak and now a researcher at the National Institute of Biology in Slovenia.
A solution to combat pollution?
Every year, around 8 million tons of plastic are dumped into the world’s oceans. The natural progress of plastic degradation is very slow: the useful life of a PET bottle, for example, can be up to hundreds of years. The growth of this waste is a global problem and there is a growing need for solutions to manage it. The researchers believe that their results have the potential to discover and adapt enzymes for new recycling processes.
“The next step would be to test the most promising candidate enzymes in the lab to closely investigate their properties and the rate of plastic degradation they can achieve. From there, microbial communities with specific degradation functions for specific polymer types can be engineered,” says Zeleznik.
