A team of researchers may have found the solution in the fight against pollution. A material that can self-destruct at the end of its life
An international team of scientists has managed to design a biodegradable material composed of bacteria with the ability to decompose at the end of its useful life.
The invention brings a ray of hope in the face of one of the most serious environmental problems, plastic pollution, reports EFE.
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"Living plastic", as defined by researchers in a study published on May 7 in the journal Nature Communications, is a soft material made of thermoplastic polyurethane that can be used to produce footwear, mats, cushions or memory foam.
The material is composed of bacterial spores of a strain of Bacillus subtilis, a common soil bacterium which, when exposed to the nutrients present in compost, germinates and decomposes this plastic material at the end of its life cycle.
"This is an inherent property of these bacteria", explained one of the study’s authors, Jon Pokorski, professor of nanoengineering at the University of California, San Diego, United States.
Scientists used bacterial spores due to their resistance to harsh environmental conditions.
Unlike fungal spores, which have a reproductive function, bacterial spores possess a protective protein shield that allows bacteria to survive in a vegetative state.
"Plastic-eating" bacteria
To manufacture the new biodegradable plastic, the researchers introduced Bacillus subtilis spores and thermoplastic polyurethane granules into a pressing machine, where the two components were mixed and melted at 135 degrees Celsius.
The researchers then evaluated the biodegradability of the resulting material by placing it on active and sterile compost residues at 37 degrees Celsius, with a relative humidity of 44-55%.
Water and other nutrients in the compost triggered the germination of the spores in the plastic, which was biodegraded by 90% within five months.
"It is unlikely that most of these plastics will end up in microbe-rich composting facilities. Therefore, this ability to self-degrade in an environment without additional microbes makes our technology even more viable", Pokorski said in a statement.
Researchers admit they have not yet studied the remains of the degraded material, but believe that persistent bacterial spores in it would be harmless because Bacillus subtilis is a strain used in probiotics and is generally considered harmless to humans and animals and even beneficial to plant health.
In this study, bacterial spores were modified to withstand the high temperatures required for polymer production.
"We evolve the cells over and over again until we reach a strain optimized to tolerate heat", explained another study author, Adam Feist, a researcher at the same university.
Although the current study focuses on producing a small amount of the new plastic material at the laboratory scale to analyze its viability, the researchers are now working on optimizing the process for industrial-scale production of plastic that self-destructs at the end of its useful life.
