Beijing, May 6 (Xinhua) -- A new type of plastic embedded with a type of bacterial spores degrades rapidly after contact with soil, according to a new study published in the British journal Nature Communications. The bacterial spores will remain dormant during the plastic's use, but will "wake up" and help degrade the plastic after it is discarded. The technology is expected to help alleviate the plastic pollution problem.

Thermoplastic polyurethanes are widely used in products such as phone cases, shoes and auto parts, but recycling rates for this type of plastic are currently low, and much of it ends up in landfills or in the natural environment. Traditional methods of developing biodegradable polyurethanes often sacrifice the polymer's mechanical properties, making it difficult to achieve industrial mass production.

Researchers from the University of California, San Diego and other institutions have developed biodegradable, commercially available plastic polyurethanes by embedding spores of the plastic-degrading Bacillus subtilis.

The bacteria have been genetically engineered to withstand the extreme temperatures required to produce plastic, and the resulting spores can survive plastic processing temperatures of 135 degrees Celsius almost completely. The plastic embedded with the spores is discarded in a simulated environment and exposed to specific nutrients in the compost, a condition that triggers rapid biodegradation of the plastic. The researchers found that plastic polyurethane embedded with the bacterial spores biodegraded more than 90 percent of the plastic within five months, and made the plastic about 37 percent more ductile than thermoplastic polyurethane without the bacterial spores.

The researchers believe that this new polyurethane containing Bacillus subtile spores is expected to replace the past non-recyclable thermoplastic polyurethane, as an environmentally friendly potential, mechanical toughness and rapid degradation of the choice.

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