A new plastic can be self-degrading with the help of bacterial spores
A new study published in the British journal Nature Communications shows that a new type of plastic embedded with a bacterial spore can degrade rapidly after contact with soil. The bacterial spores remain dormant during the use of the plastic, but will "wake up" and help degrade the plastic after the plastic is discarded. This technology is expected to help alleviate the problem of plastic pollution.
Thermoplastic polyurethane is widely used in products such as mobile phone cases, shoes, and auto parts, but the recycling rate of such plastics is currently low, and most of them end up as landfill waste or enter the natural environment. Traditional methods for developing biodegradable polyurethanes usually sacrifice the mechanical properties of the polymer, so it is difficult to achieve industrial mass production.
Researchers from the University of California, San Diego and other institutions have developed biodegradable commercial plastic polyurethane by embedding spores of Bacillus subtilis that can degrade plastics.
After genetic engineering, this bacterium can withstand the extremely high temperatures required to produce plastics, and the resulting bacterial spores can survive almost completely at the plastic processing temperature of 135 degrees Celsius. The plastic embedded with the spores was discarded in a simulated environment and exposed to specific nutrients in the compost, which can initiate the rapid biodegradation of the plastic. The researchers found that the plastic polyurethane embedded with the above-mentioned bacterial spores can achieve more than 90% biodegradation of plastic in 5 months, and can also make the toughness of the plastic about 37% higher than that of thermoplastic polyurethane without the embedded bacterial spores.
The researchers believe that this new type of polyurethane containing Bacillus subtilis spores is expected to replace the previously non-recyclable thermoplastic polyurethane and become an environmentally friendly option with strong mechanical toughness and rapid degradation.
