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Polyhydroxyalkanoic Acids (Spiderman Bacteria)

By moleculeoftheday on September 28, 2006.

(Oops, this should have been published on Tuesday. I didn't click publish. Sorry!)

Certain bacteria, under certain conditions, will excrete plastic.

The one above is a polybutyrate, but many are possible.

This is neat, first of all, because it's bizzare. Can you imagine being able to excrete plastic?:

To produce PHB a culture of a micro-organism such as Alcaligenes eutrophus is placed in a suitable medium and fed appropriate nutrients so that it multiplies rapidly. Once the population has reached a substancial level, the 'diet' is changed to force the micro-organism to create PHB. Harvested amounts of PHB from the organism can be anywhere from 30% to 80% of the organisms dry weight.

(wikipedia)

Think about that number, too - imagine being able to excrete tens of pounds of plastic. Beyond the gee-whiz factor, these polymers are being looked at because they're presumably biocompatible (and therefore good for stuff like dissolving sutures). Also, stuff like yesterday's molecule is green in that it's biodegradable (and "made from corn,") but you have to do quite a bit to the corn to get it there (including, I'll bet, a step where you let the bacteria munch on the corn to generate the lactic acid). Getting it out of a bacteria is one step (ignoring purification, etc.)

Amusingly there are people who try to make poly-4-butyric acid (or rather, poly-GHB.) Of course, they all know perfectly well what molecule they're working with, but the idea of people trying to hydrolyze out GHB (or just munching on the plastic) boggles the mind.

Tags
Polymers

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Why is polyisobutyrate used to store calories and for structural support any more bizarre than polyanhydroglucose? The difference is that "cultured" plastics from fermentation vats cost dearly while starch grows on bushes and wood grows on trees for cheap. Don't you dare make Frankenplastic from gene-gineered optimized organisms. UNKNOWN HAZARDS!

Oil efficiently recovered for cheap from oil wells, bad. Oil horrendously recovered for big bucks from Canadian Athabasca tar sands plus massive aqueous waste discharges, good. Whatever you have of value, Enviro-whiners demand it be destroyed.

Grow wood, get oxygen. Grow PHB, destroy the Earth. More studies are needed.