Clostridium acetobutylicum

Clostridium acetobutylicum, included in the genus Clostridium, is a commercially valuable bacterium. It is sometimes called the "Weizmann Organism", after Chaim Weizmann, who in 1916 helped discover how C. acetobutylicum culture could be used to produce acetone, butanol, and ethanol from starch using the A.B.E. process (Acetone Butanol Ethanol process) for industrial purposes such as gunpowder and TNT production. The A.B.E. process was an industry standard until the late 1940s, when low oil costs drove more-efficient processes based on hydrocarbon cracking and petroleum distillation techniques. C. acetobutylicum also produces acetic acid (vinegar), butyric acid (a substance that smells like vomit), carbon dioxide, and hydrogen.

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Anaerobic fermentation using C. acetobutylicum recently regained marked interest for use in vehicle fuel production as a gasoline and diesel fuel replacement. This is because butanol, as produced by a fibrous bed bioreactor utilizing recent biotechnology co-developed by Environmental Energy Inc. and Ohio State University, produces the alcohol butanol as its primary output. The patented process using C. tyrobutyricum produces little acetone or ethanol, instead producing butyric acid and hydrogen, which is then pumped into another fibrous bed bioreactor where C. acetobutylicum converts the butyric acid into butanol, thus optimizing butanol production. The new process, then, obviates the A.B.E. process, making butanol production competitive with other biofuels with regard to both economics and energy production.

Pure butanol can be utilized in gasoline-powered cars without any modifications, producing similar mileage performance to gasoline but producing fewer NOx pollutants. If produced from a biomass source, there is no net carbon dioxide production.

Unlike yeast, which can digest sugar only into alcohol and carbon dioxide, C. acetobutylicum and many other Clostridia can digest whey, sugar, starch, lignin, cellulose fiber, and other biomass directly into butanol, propionic acid, ether, and glycerin. Apart from the need for temperature control, the A.B.E. synthesis process is relatively simple. The products are formed in layers that are easy to separate.

Biobutanol supporters claim significant advantages over other biofuels used to fuel internal combustion-based vehicles and other liquid-fueled processes:

• Butanol has a higher octane fuel value than gasoline with increased low-end torque. A V8 engine has been tested on a 10,000-mile U.S. tour supporting a U.S. Department of Energy grant in 2005. The results of the butanol auto fuel demonstration were presented to the U.S. Department of Energy National Renewable Energy Laboratory's Clean Energy Forum in San Francisco on November 7, 2005.
• Butanol can be produced for less than fossil-based vehicle fuels.
• Butanol reduces vehicular emissions.
• Butanol does not readily adsorb moisture (it is not hygroscopic), so is less affected by changes in the weather, unlike the combustion of pure ethanol, which requires engine and fuel system modifications.

• Butanol does not attack materials commonly used in vehicular internal combustion engines.
• Biobutanol can also be used in the industrial paint and solvent industry to replace fossil butanol.

See also

• Biobutanol