In the Dec. 1979 issue we made the acquaintance of Thiobacillus ferrooxidans, the microbe that attacks metal ores. It was used to mine iron and copper by the Romans in antiquity and by the Spaniards in the 17th century, though its employers had no idea what was going on.
The news then was that the little bug was going nuclear, eating uranium by dissolving it in acid and enabling the metal to be solution-mined.
The news this month is far more momentous: there is good reason to hope that genetic engineering can develop bugs to mine coal. How is it done, and why is this momentous?
First, let me slightly correct the news. They are not all bugs, but fungi, and they have been developed already; but there are some bugs to be ironed out in the fungi, and the economics of the process are still in doubt unless production can be substantially speeded up.
In essence, these microbes eat coal and excrete fuel either as liquefied coal or as methane gas. The effect was discovered in 1981 when makers of a wood preservative studied the fungi responsible for wood rot. It occurred to one of them that lignite ("wood coal") had a molecular structure similar to wood, and that some fungi might rot coal into a liquid
¾a more efficient and cheaper process than the one never developed for the billions given by Carter to the Synthetic Fuels Corporation. Sure enough, one of the wood-rotting fungi with the humiliating name of Polyporous versicolor (sounds like photo-film full of holes, doesn't it?) grew well on a lump of coal and turned it into a gooey liquid within a week. The scientists, Prof. Martin Cohen of the U. of Hartford, Conn., and Peter Gabriele, an employee of the makers of Cuprinol wood preservative, sent the report to Science, which rejected it because the reviewers did not believe it. (Some years ago, a French friend of mine had a paper re-jected by the J. of Terrestrial and Atmospheric Research on the grounds that paragraph so-and-so on page so-and-so "contradicts generally accepted theory.") But they published elsewhere and today several research institutes, including Battelle and EPRI (Electric Power Research Inst.) are intensively investigating the process.The discovery came at the right time. Had it been made earlier (and who knows, perhaps it was made earlier, like so many others that have been forgotten because they were made "too early"), it might not have been of much use. Coal is such a heterogenous material, and varies so sharply from site to site that a single fungus or microbe could not be used for all kinds. Houston Power & Light, for example, has hired a scientific company to look for "a bug that will eat lignite in a salty environment, doesn't breathe oxygen, and excretes methane."
As yet, they are looking for the right bug in places like the bot-tom of the Great Salt Lake; but the time is fast approaching (though it has not yet arrived) when genetic engineering will be able to produce such a bug according to specifications, much like chemistry can now produce many hitherto nonexistent compounds with specified properties rather than, as it once had to, looking for them among already existing materials. Perhaps the needed bug can be engineered from Escherichia Coli, which resides in the intestines of Mr. Jeremy Rifkin.
Meanwhile the ancient Romans' employee Thiobacillus ferro-oxidans is put to work, too. It doesn't mine coal, but cleans it. In a flotation process meant to float the coal and make the impurities sink, many of the small sulfur-carrying pyrite particles tend to be repelled by water and are kept afloat with the coal dust. There are countermeasures, but they get rid of the pyrite only at the price of losing much of the coal. Enter Thio the Ironoxidizer (that's what the Latin means). This time he does not work as a chemist dissolv-ing metal, but as a physicist messing up the pyrite: he leaves im-purities, including himself, on the pyrite particles, causing them to sink. When ground coal is soaked in a rich bath of Thiobacilli for 15 minutes (as yet only in the lab), the sulfur removal percentage is doubled for the same amount of the recovered coal (80% to 90%).
But Thio can do nothing about organic sulfur, bound up chemically with carbon, hydrogen and other atoms. What is needed here is a bug that eats such compounds, destroying their chemical structure. Alas, you can take a bug to the sulfur, but you can't make it drink.
Not a natural bug, anyway. But you can engineer one (breed it, in this case) by mutations and selections after giving it a compound believed to have the same molecular structure as organic sulfur in coal. You tell him it's either this or nothing, boy, and after a few generations he cries out for what he has been fed on like an addicted reader of the New York Times. Researchers at Atlantic Research Corp., Alexandria, Va., gave this treatment to Pseudomonas, another old acquaintance of ours
¾that's the bug which was taken to court by Jeremy Rifkin for being engineered to a "Frostban" bug, preventing damage by early frosts and probably being able to save the California strawberry crop from early frosts.The genetically changed Pseudomonas has been given the name CB1 (for Coal Bug One); a second strain, CB2, is also ready. The two of them will remove somewhat less than 60% of the organic sulfur in coal in 9 hours
¾in the lab.But as the Age of Biology is dawning, they whistle "More! " and "Faster!" while they work.
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Vol. 15, No. 3
Newsletter: Access to Energy Newsletter Archive Volume: Issues Issue/No.: Vol. 15, No. 3 Date: November 30, 2004 03:51 PM Title: Gulf oil
Copyright © 2004 - Access to Energy Newsletter Archive
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