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R&D News: Eco-Friendly Way of Degrading BPA-Plastics

What was done?

I came across an interesting article yesterday titled “Biodegradation of Physicochemically Treated Polycarbonate by Fungi” published in Biomacromolecules. What this group essentially did was to isolate fungi from the environment by exposing them to conditions in which plastics were the only source of food. The group basically identified three fungi (Phanerochaete chrysosporium, Engyodontium album  and Pencillium spp.) , and characterized some of the parameters by asking basic questions about:
  • Efficacy changes when fungal isolates were exposed to certain pre-treatments (either heat or UV light).
  • Growth of biomass (how much the fungi grew during this time)
  • How much extracellular protein was secreted and a crude determination of the class proteins released
  • Loss of mass of the piece of plastic
  • Changes in physical, chemical and surface properties.

Why is this important?

I asked myself the same question until I realized what plastic they were working with: Bisphenol A Polycarbonate or BPA containing plastics in other words. BPA is used to create clear, and shatter-free plastics.

For those who don’t know, BPA has recently entered the health news because of concerns on its effect on human health. The effects of BPA were first accidentally discovered in laboratory rats in which female mice all of a sudden had reproductive problems after changing the wash detergent used to clean the animal cages. The sudden effects puzzled the researchers until they were able to find the cause: The new detergents used in cleaning the animal cages dislodged BPA from the plastics. BPA was determined to be an endocrine disruptor in rats which means that it basically disrupts the hormonal cycles especially in female rats leading to fertility problems. The astonishing discovery was that the effects of BPA did not only affect the rat who was exposed to BPA, but that even the children of the mother were still affected. Although the plastics industry has officially stated that the human effects have largely been undetermined, many producers have voluntarily phased out the use of BPA due to pressure from consumer groups as well as the general scare within consumers.

What is the take-home message?

Although the use of BPA has been phased out, the question remains what will happen to all the plastics that have already been produced. What happens for instance when BPA leaches out of the plastics in land-fills and enters the ground water system where often times drinking water is drawn from? BPA has already been shown to have leached into the oceans where many scientists are very concerned about BPA's effects on marine life. This article crudely shows that we can safely bio-degrade BPA-containing plastics without releasing BPA to the environment. In previous articles, I have talked about how bacteria, or algae can be used to bioremediate (clean up the mess we produced) different sorts of pollutants. This article shows the potential of using certain fungi in the bio-degradation of BPA plastics.

Literature Cited

Trishul Artham and Mukesh Doble. "Biodegradation of Physicochemically Treated Polycarbonate by Fungi." Biomacromolecules, 2010, 11 (1), pp 20–28. Link: http://pubs.acs.org/doi/abs/10.1021/bm9008099

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