Global Challenges/Chemistry Solutions

Our Sustainable Future: Decomposing BPA-containing plastic using a “fungus among us”

May 14, 2010


Fungi may provide an eco-friendly
way of decomposing polycarbonate
plastic waste that contains bisphenol A.
Credit: American Chemical Society.
(High-resolution version)

  Summary

Scientists are reporting discovery of a more sustainable way of disposing of plastics that contain bisphenol A (BPA) — without releasing that potentially harmful substance to the environment. The new method involves exposing polycarbonate plastic waste to ultraviolet light and heat. Just as cooking makes food more digestible for humans, this pretreatment approach makes polycarbonate plastic more digestible for certain fungi, which the scientists used to break down polycarbonate plastic. Their study appears in the ACS’ monthly journal Biomacromolecules.

 

Polycarbonate plastic is everywhere. It’s used in screwdriver handles, eyeglass lenses, DVDs, CDs, and food containers. Although versatile and durable, polycarbonate contains a controversial chemical called bisphenol A, or BPA. Some studies have linked BPA exposure to a variety of health problems. Manufacturers make about 2.7 million tons of plastic containing BPA each year. Consumers trash products containing that plastic, and it fosters concerns about how to dispose of the resulting waste in a sustainable fashion. Dr. Mukesh Doble [pronounced Moo-kesh Dough-blay], a scientist with the Indian Institute of Technology Madras, may have a solution. He reports discovery of a new way to dispose of BPA-plastic that involves using fungi. They’re members of a family that includes yeasts, molds, and mushrooms. Just as cooking helps turn food into a form that people can easily digest, pretreating polycarbonate plastic a certain way helps make the plastic more digestible for certain fungi, which the scientists use to breakdown the plastic. The study appears in the ACS’ monthly journal Biomacromolecules. Here is Dr. Doble:

“I would say it’s one of the first studies that look at the degradation of polycarbonate which contains BPA.”

Doble and his colleagues pretreated polycarbonate with ultraviolet light — which is found in sunlight — and heat. Then they exposed the pretreated plastic to three kinds of fungi. The fungi included the fabled white-rot fungus, used commercially for environmental clean-up of the toughest pollutants. The scientists found that fungi grew better on pretreated plastic. The fungi used BPA and other ingredients for energy and helped break down the plastic.

Here again is Dr. Doble:

“After 12 months, there was almost no decomposition of the untreated plastic, compared to substantial decomposition of the pretreated plastic, with no release of BPA. I think it’s important because at least now we know there are ways of degrading polycarbonate without actually releasing BPA. It’s a very important finding.”

Who knew that a little “fungus among us” could provide such a clever solution to a big environmental problem and speed us along the road to a sustainable future?

Smart Scientists/Innovative Thinking

That’s the key to solving global challenges of the 21st Century. Be sure to check our other podcast on Our Sustainable Future: Small generator, Big applications. Today’s podcast was written by Mark Sampson. I’m Adam Dylewski at the American Chemical Society in Washington.