Slashdot Mirror
Solar Powered Microbes Manufacture Biofuels
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."
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.
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.
Corn for just ethanol is a bad idea, but corn pressed to remove the oil for biodiesel,
sugar removed for fermentation to ethanol
the stover used for cellulose conversion,
and the high protein distiller's dried grain fed back to cattle for food production, not so bad.
Apocalypse Cancelled, Sorry, No Ticket Refunds
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.
A polar bear is a cartesian bear after a coordinate transform.
If there is a better source of ethanol that comes around, then so be it. Corn ethanol has stimulated development of the next generation of technology.
Implicit in the parent's argument is the idea that ethanol competes for food crop acres and thus raises prices. That is correct. However, the sensationalist media and proponents of other energy alternatives neglect several components of the equation. One component is the argument that high food prices is bad for the third world. The argument seems confusing when you discover that these are usually the same people that argue farm subsidies are causing food prices to be too low . Recent Wall Street Journal articles indicate that high crop prices are finally stimulating investment in third world agriculture. Another component is the argument that today's high food prices are because of ethanol. This is also confusing because similar price increases have been witnessed in products that have nothing to do with corn production. Rice for example, has shown the same percentage jump and yet does not compete with corn acres. My last point is that fuel prices are a major cost of corn production. If we eliminated ethanol production today, the increase in fuel prices due to reduced dilution from ethanol would mean that food prices would hardly change (if at all). [Note this is a little too simplistic because eliminating ethanol would distribute increased fuel costs over a market broader than agriculture - the net effect is the same].
I am not arguing that tying energy and food production together can't be dangerous. I am arguing that we haven't reached that point. Further, in a sense, energy and food production have always been tied together.
Why have 1 person driving a backhoe when you could employ 20 with shovels?
I was figuring a desert type environment, with salt water pumped in more or less straight to provide the water would be a lot cheaper than many other environments. Fresh water is getting expensive.
As for release into the wild, most likely not a big deal - conditions conductive to their growth isn't universal, areas conductive probably have non-altered species of cyanobacteria already that are more competitive.
I don't read AC A human right
Double fuel mileage and you only need 14350 square miles. Get commuters on more public transit: 12000 square miles. Get 25% of the cars on the road to go electric, 9000 square miles.
That might be harder than you think. We're already making cars that go 30mpg. Maximum theoretical milage is around 120mpg. Doubling milage would put us at 50% of the theoretical maximum, which would be a very impressive technical feat. Getting more cars off the road would help, but switching to electric just means you're getting your power somewhere else.
Give me Classic Slashdot or give me death!