Scientists have discovered a bacterium that feeds on toxic plastic. The bacteria not only break down the plastic but use it as food to drive the process.
The bacteria, found at a waste site where plastic was dumped, is the first known to attack polyurethane. Millions of tons of plastic are produced each year for use in items such as sports shoes, diapers, kitchen sponges, and as foam insulation, but it is mainly sent to landfill because it is too difficult to recycle.
When it decomposes, it can release toxic and carcinogenic chemicals that would kill most bacteria, but the newly discovered strain can survive. While research has identified the "worm" and some of its key characteristics, much work remains to be done before it can be used to treat large amounts of plastic waste.
"These findings represent an important step in being able to reuse hard-to-recycle polyurethane products," said Hermann Heipieper, of the Helmholtz Center for Environmental Research-UFZ in Leipzig, Germany, who is one of the members of the research team. He said it could be 10 years before the bacteria could be used on a large scale and that in the meantime it was vital to reduce the use of plastic that is difficult to recycle and to reduce the amount of plastic in the environment.
More than 8 billion tons of plastic have been produced since the 1950s, and most of it ended up polluting the world's land and oceans, or landfills. Scientists say it threatens "almost permanent contamination of the natural environment."
The research, published in the journal Frontiers in Microbiology, identified a new strain of Pseudomonas bacteria, a family known for its ability to withstand harsh conditions, such as high temperatures and acidic environments.
Investigators gave him key polyurethane chemicals in the lab. "We found that bacteria can use these compounds as their sole source of carbon, nitrogen and energy," Heipieper said.
Fungi have been used before to break down polyurethane, but bacteria are much easier to harness for industrial use. Heipieper said the next step would be to identify the genes that encode the enzymes produced by the insect that break down polyurethane.
Scientists revealed in 2018 that they had accidentally created a mutant enzyme that breaks down plastic beverage bottles, which are made from PET, potentially allowing for full recycling of the bottles for the first time. One of the teams behind this breakthrough, Professor John McGeehan, director of the Center for Enzyme Innovation at the University of Portsmouth, England, praised the new work.
“The breakdown of certain polyurethanes can release toxic additives, which must be handled with care. This research group has discovered a strain that can tackle some of these chemicals, "he said. “While much work still needs to be done, this is exciting and necessary research that demonstrates the power of looking at nature to find valuable biocatalysts. Understanding and taking advantage of these natural processes will open the door to innovative recycling solutions ”.
Heipieper said: “When you have large amounts of plastic in the environment, that means there is a lot of carbon and there will be an evolution to use it for food. Bacteria are there in large numbers and their evolution is very fast ”.
"However, this certainly does not mean that the work of microbiologists can lead to a complete solution," he maintained and closed: "The main message should be to prevent plastic from being released into the environment in the first place."
Previous research has also shown that some fungi can break down PET plastic, while wax moth larvae, usually raised as fish bait, can eat polythene bags.