I read the below article in Wired a few days ago and was so struck by it that I had to write about it here. A friend and I had talked about this very topic the previous Sunday while hiking south of Denver, so this was already on my mind.
http://www.wired.com/science/planetearth/magazine/15-10/ff_plant_formula
The article stresses that the process itself involved in the production of ethanol is fairly straight-forward:
- Thermochemical treatment The raw plant feedstock is treated with chemicals — often diluted sulfuric acid — to break down cell walls and make the cellulose accessible.
- Enzymes A mix of cellulase enzymes is then added to convert the cellulose and hemicellulose molecules into the simple sugars glucose and xylose.
- Fermentation Yeast or bacteria are added, converting the sugar into a mixture of ethanol and water, what refineries call "the beer."
- Distillation The ethanol is refined and purified, producing a fuel that could one day end up in your gas tank.
This echoed what I already knew (at least marginally understood anyway), but I was surprised to hear that the biggest barrier to large-scale production of ethanol is the molecular structure of cellulose, and the difficulties involved in breaking down that structure. I was under the impression that this particular problem had been solved & was scalable. There are approaches, to be sure, of breaking down cellulose to produce cellulases, but apparently none so far has proven cost-effective (translation: it isn’t profitable).
I was even more surprised - pleasantly so - at the amount of research currently being funded on this & other renewable energy sources. I had argued with my friend that substantial research wasn’t being conducted into renewable energy sources now, mostly because the political climate didn’t favor it. I was wrong, and that’s great. I do feel somewhat vindicated, though, to see the Wired article point out one of my primary assertions: that when Reagan declared the energy crisis over in the 80s, federal funding of energy research vanished nearly overnight. And it has taken twenty years to correct that mistake.
Tags: ethanol, energy, cellulose, cellulases

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