July 7, 2010

Bacteria eating plastic

We can all see we're drowning in plastic. Even our oceans our drowning in jettisoned gyres of plastic bottles, rope, bags, and styrofoam packaging. (See my Sept. 21, 2008 post.)

Here's the deal: even if we drastically reduce our consumption of plastic, we will still have left over 7o pounds of plastic debris for the next 4,000 generations of humans to deal with. We must come up with ways of transforming the waste plastic into compounds that can be used by natural processes. That is, we have to find ways that nature can help us biodegrade what are indigestible chemical bonds. Plastics wouldn't be so useful if their long-chain polymers weren't bonded in such a way that bacterial and fungal enzymes could break them.

Daniel Burd, a high school student in Waterloo, Ontario, isolated two bacterial strains that were capable of decomposing the polyethylene in grocery bags. A Sphingomonas sp. and a Pseudomonas sp. digested 43% of the plastic after six weeks in liquid culture.

Daniel Burd's science fair project.

This is the kind of thinking and experimentation that could lead to real solutions for ridding our planet of waste plastic.

One of the greatest sources of litter in Canada is Tim Hortons cups. They're in almost every ditch, on the sidewalks, all over urban and suburban fields. They are neither compostable nor recyclable because they have a plastic lining. David Levin and Richard Sparling of the University of Manitoba have found a way to turn Tim Hortons cups into biofuel. Although it deals with the conversion of paper to a usable product, the concepts behind the research point the way to finding methods for digesting plastic. They created a solution of cups and bacteria that shows that the bacteria create biofuel.

CBC's The National piece.


Sarah said...

Have you seen this short film yet?

annie said...
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This comment has been removed by the author.

I don't know whether to thank you for introducing me to Futurestates.tv or not. That film is very beautiful and worth watching all the way to the end. It makes me FEEL differently about plastic bags. But thinking about the end of the world, or envisioning it as they do in these videos, makes for anxious middle of the night thoughts.