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esocid alerts us to news that scientists from the University of Texas at Austin have created a microbe capable of making cellulose, which can then be turned into ethanol. The bacteria use sunlight as an energy source, and the cellulose can be harvested without destroying them. Quoting:
"The new cyanobacteria produce a relatively pure, gel-like form of cellulose that can be broken down easily into glucose.
'The problem with cellulose harvested from plants is that it's difficult to break down because it's highly crystalline and mixed with lignins [for structure] and other compounds,' Nobles says. He was surprised to discover that the cyanobacteria also secrete large amounts of glucose or sucrose, sugars that can be directly harvested from the organisms."
According to the article, the approximate area needed to produce ethanol with corn to fuel all U.S. transportation needs is around 820,000 square miles, an area almost the size of the entire Midwest.
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That seems to be the problem with every story about revolutionary technology. A mention on slashdot every couple years, then nothing.
It looks like they they need to control the simple sugar secretion problem. This is not only an organism which wastes energy (from its "perspective") for no good reason by making cellulose but also an organism which is considerate enough to potential competitors to give them an easy to use energy source in the form of simple sugars.
The former (the part we want) makes the organism weak but might be manageable. The latter, makes the organism "stupid" and, if it produces large enough quantities of simple sugars to sustain high densities of other microbes feasting on simple sugars, suicidal since secondary metabolites (or simply overwhelmingly high numbers of competitors) will probably make a population of this organism unsustainable.
On an unrelated note, I'd like to point out the last lines of TFA: Brown and Nobles are now researching the best methods to scale up efficient and cost-effective production of cyanobacteria. Two patent applications, 20080085520 and 20080085536, were recently published in the United States Patent and Trade Office. Patents on biological processes are never good. What are these patents and what does this mean?
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The BBC article (which is misreporting the endosymbiont hypothesis badly enough to make Lynn roll in her grave were she not still alive) was actually reporting on an article investigating homologies of cellulose synthases in several species of cyanobacteria. Curiously, the current U of Texas at Austin is not about harnessing native cellulose production by some cyanobacterium but rather about "Transgenic expression of Gluconacetobacter xylinus strain ATCC 53582 cellulose synthase genes in the cyanobacterium Synechococcus leopoliensis strain UTCC 100". I guess that they decided that inserting required cellulose biosynthetic enzymes from an organism (apparently) known to produce a lot of cellulose was easier than trying to optimize the miserly levels of cellulose biosynthesis in some cyanobacterium.
[no, I'm always this grumpy, thanks for asking] In the past productivity has gone through the roof when they went outside, even the article said a 17X increase was possible. in Arizona an algae CO2 capture plant had to be shut down because the bioreator's production increase overwhelmed the processing plant! Give them a chance and let's see what happens in the real world.
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It's not necessarily suicidal.
Cyanobacter are routinely part of lichens, which are a very weird mix of fungi and bacteria capable of photosynthesis. The fungi form a matrix in which the bacteria are trapped, and help collect minerals and moisture for the trapped bacteria.
The arrangement isn't entirely mutually beneficial, from the point of view of the individual bacteria, but from a propagating-the-genes point of view (which in evolution is the only one that matters at all) it does allow the bacteria to live and multiply in some places where it otherwise could not.
And the fungi aren't doing it as some kind of act of kindness, either: fungi can't do photosynthesis on their own, so those lichens growing on rocks and whatnot, well, would die if noone in that arrangement provided food for the fungi too. That's the bacteria's contribution there: those sugars.
At any rate, it's sorta like being inside a living test tube full of nutrients and water. If you don't produce an excess of sugars, the test tube dies. Clearly there's a survival advantage in avoiding that.
From another point of view, fungi are nasty critters, which can only live on organic matter produced by someone else. It may be parasitic (they take other cells apart and eat them) or they can live on dead matter, but nevertheless they absolutely need someone else to manufacture those nutrients for them. Most of those in lichens are a highly specialized and adapted form of parasite. They don't just live off the nutrients that the bacteria excrete, but actually poke the bacteria with tiny filaments and suck the nutrients right out of the living cell. The trapped bacteria are routinely killed in the process, but the colony survives by just allowing them to multiply faster than they're killed.
Again, it's a survival advantage to be able to produce enough of an excess of nutrients, so you can survive (and make enough of a reserve to divide too) even with 3-4 fungal cells around you, all living off you.
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TFA describes an approach with nice potential, but it seems to need a lot of work before it becomes commercially viable.
Another is oil from algae: http://en.wikipedia.org/wiki/Algaculture#Algae_as_an_energy_source
and it seems to be closer to commercial use.
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