Plastic eating bugs
Tuesday, 2 February 2010 | Lewis
by the Green Goblin
Irish Bugs Recycle Plastic
My mother is a Leprechaun, but she enjoys a good joke now and again - the kind that are supposed to show how 'thick' the Irish are. Of course, we all know that this is a myth. The truth is rather different. Ireland is full of very canny people.
One of them, Dr Kevin O'Connor BSc. PhD., of University College Dublin, has discovered bugs that eat oil based plastic (PET) and turn it into more useful plastic (PHA) - the kind often used for medical purposes.
Gas for energy
Actually there are two products involved in this process. First of all, you heat the plastic up, making sure not to allow any oxygen to get into the equation. This produces a gas which can be used for heat and energy. I mentioned yesterday that a friend of mine is already using this process for recycling waste plastic and is syphoning off the gas successfully.
The heating of the plastic also produces terephthalic acid, known in the trade as TA. Some very particular bugs, commonly found inhabiting places that make PET plastics, love the taste of TA like women love chocolate. They can't get enough of it.
The nitty gritty detail
If you really want to know what the bugs are, I'll tell you. But most of us will be none the wiser. They are Pseudomonas bacteria. There are 3 suitable varieties found by Dr O'Conner.
When digesting the PET plastic they effectively recycle it, turning what was headed for landfill, into a biodegradable plastic called polyhydroxyalkanoate or PHA. It's a thermo-plastic elastomer. This means it is resistant to higher temperatures than other plastics, and is also very stretchy stuff.
Food or plastic?
These special properties of PHA, now produced successfully by O'Connor's bugs, make it perfect for medical use. AT present PHA is manufactured commercially from corn and sugar. These are grown for that purpose on precious arable land.
There is already a lot of fuss being made about biofuel which is also manufactured from corn and sugar. It must be said that crops people don't actually get to eat, when so many people are barely able to feed themselves, just so we can have stretchy plastic, is a bit indigestible.
Consequently, Dr O'Connor's research is very attractive to governments and commercial interests, and is sure to get continued funding.
Supermarkets salivating for plastic
Did you know that 80% of oil based plastic - PET plastic - ends up in landfill? And the biggest users of plastic are those making and selling fast moving consumer products.
No surprises there. It's all in the packaging. So, as one might expect, supermarket chains are licking their lips at the thought of cheap, eco acceptable plastic, that biodegrades. It could easily be used for food packaging and plastic carrier bags.
These plastic consuming businesses will be able to shout about their green credentials and still use lots of plastic. It would all be recycled plastic. Actually, it will be a step further than that, being recycled, recycled plastic. It will rot down nicely in landfill if it ends up there. So it seems the multi-use plastic bag will have a new lease of life after all.
Keep track of Kedel's recycled plastic tidbits
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And I am now going to feed some PHA to my pet Pseudomonas. Ouch! Something just bit me.