September 21, 2008

Biodegradable plastic?

Biodegradable plastic?

“As I gazed from the deck at the surface of what ought to have been a pristine ocean, I was confronted, as far as the eye could see, with the sight of plastic. It seemed unbelievable, but I never found a clear spot. In the week it took to cross the subtropical high, no matter what time of day I looked, plastic debris was floating everywhere: bottles, bottle caps, wrappers, fragments. ”

—Charles Moore, Across the Pacific Ocean, plastics, plastics, everywhere

I could chronicle all the ways plastic has messed us up. It's been screwing with us since the turn of the last century. We've got a whirlpool of plastic flotsam, a gyre of crap in the Pacific the size of, what, Texas? Alaska? Rupert's Land? Instead, why not some suggestions about how nature may be able to adapt to plastic and digest it.

Deguchi et al. reported back in 1997 that the white rot fungus, Phanerochaete chrysosporium, was capable of degrading some forms of nylon. They then isolated the enzyme responsible for this activity. See Applied and Environmental Microbiology for the reference at Purification and Characterization of a Nylon-Degrading Enzyme. It seemed that a fungal enzyme had been altered to digest nylon. After all, the stuff is full of the nutrients, like nitrogen, that microorganisms need. Normally, nothing can digest the bonds, even though they’re similar to the amide bonds of natural proteins.

Daniel Burd, an Ontario science student, won $10,000 at the Canada-wide Science Fair in 2008 for demonstrating that polyethylene shopping bags could be digested, at least in part, by soil bacteria. Although this could lead us to continue to use plastic bags without thinking, since we may believe they are now biodegradable, there’s a long way to go before this kind of technology can be applied. Good riddance to plastic bags?

If you want to know about the world’s largest garbage dump – and who wouldn’t? - Great Pacific Garbage Patch.


Meanwhile, we've got a store here in Halifax that's gone bag-free. Well, not quite bag-free. The cashiers won't give you a bag but the store will sell you thick plastic bags for a buck. It's a great way to raise consumer awareness that, ultimately, our habits have to change. It's also a great way for them to market another product. Now, instead of giving away all those polyethylene bags that are part of the Great Pacific Garbage Patch, they can sell them to us!

1 comment:

annie said...

Hey smarty-pants...
nice blog.
A