The number of microbial enzymes with the ability to degrade plastic is growing, in correlation with local levels of plastic pollution. That is the finding of a study from Chalmers University of Technology, Sweden, that measured samples of environmental DNA from around the globe. The results illustrate the impact plastic pollution is having on the environment, and hint at potential new solutions for managing the problem.
The study analyzed samples of environmental DNA from hundreds of locations around the world. The researchers used computer modelling to search for microbial enzymes with plastic-degrading potential, which was then cross-referenced with the official numbers for plastic waste pollution across countries and oceans. “Using our models, 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,” says Aleksej Zelezniak, Associate Professor in Systems Biology at Chalmers University of Technology.
More enzymes in the most polluted areas: In other words, the quantity and diversity of plastic-degrading enzymes is increasing, in direct response to local levels of plastic pollution. In total, over 30,000 enzyme ‘homologues’ were found with the potential to degrade 10 different types of commonly used plastic. Homologues are members of protein sequences sharing similar properties. Some of the locations that contained the highest amounts were notoriously highly polluted areas, for example samples from the Mediterranean Sea and South Pacific Ocean…
The researchers believe that their results could potentially be used to discover and adapt enzymes for novel recycling processes…“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. From there you could engineer microbial communities with targeted degrading functions for specific polymer types,” explains Aleksej Zelezniak.
Plastic-degrading enzymes increasing in correlation with pollution, Chalmers University of Technology Press Release, Dec. 14, 2021