Recently a bug or bacterium has been discovered by the scientists that feed on toxic plastic. This bug or bacterium is not only able to break down the plastic or polyurethane, which is widely used and rarely recycled but also uses it as food to power the process.
The bacterium is the first that is known to attack polyurethane found at a waste site where the plastic had been dumped. Every Year, plastic in millions of tonnes are produced to be used in items like kitchen sponges and as foam insulation, nappies, and sports shoes. However, being too tough to recycle, it is mostly sent to landfill.
Usually, plastic releases toxic and carcinogenic chemicals when broken down and would kill most bacteria, but this newly discovered strain can survive. Although the research has identified the bug and some of its essential characteristics, it requires more research before using it to treat large amounts of waste plastic.
“These findings represent an important step in being able to reuse hard-to-recycle polyurethane products,” said Hermann Heipieper, at the Helmholtz Centre for Environmental Research-UFZ in Leipzig, Germany, who is one of the research team. According to him, it might be 10 years before the bacterium could be used on a large scale as the reduction in the use of plastic that is hard to recycle and reducing the amount of plastic in the environment became vital.
Since the 1950s, out of more than 8bn tonnes of plastic that has been produced, most have ended up in the land and oceans, or in landfill dumps polluting the world. Scientists say it threatens “near-permanent contamination of the natural environment.”
The study 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 acidic environments and high temperatures.
The researchers fed the bug key chemical components of polyurethane in the laboratory. “We found the bacteria can use these compounds as a sole source of carbon, nitrogen and energy,” Heipieper said.
Earlier fungi have been used to break down polyurethane, but for industrial use, bacteria are much easier to harness. The next step would be to identify the genes that code for the enzymes produced by the bug for breaking down the polyurethane, Heipieper said.
It was revealed in 2018 that scientists had accidentally created a mutant enzyme that breaks down plastic drinks bottles made of PET and potentially enabling the complete recycling of bottles for the first time. One of the team members behind this advance study, Prof John McGeehan, the director of the Centre for Enzyme Innovation at the University of Portsmouth, England, praised the new work.
“The breakdown of certain polyurethanes can release toxic additives, which need to be handled carefully. This research group has discovered a strain that can tackle some of these chemicals,” John said. “While there is still much work to be done, this is exciting and necessary research that demonstrates the power of looking to nature to find valuable biocatalysts. Understanding and harnessing such natural processes will open the door for innovative recycling solutions.”
Heipieper said: “When you have huge amounts of plastic in the environment, that means there is a lot of carbon and there will be evolution to use this as food. Bacteria are there in huge numbers and their evolution is very fast.
“However, this certainly doesn’t mean that the work of microbiologists can lead to a complete solution,” he said. “The main message should be to avoid plastic being released into the environment in the first place.”
Previous research has disclosed that some fungi can break down PET plastic, while a wax moth larva that is usually bred as fish bait can eat up polythene bags.
