20 August 2009

Butanol biofuel could replace gasoline

There is now a way to double the production of the biofuel butanol, which might someday replace gasoline in automobiles.

The process improves on the conventional method for brewing butanol in a bacterial fermentation tank.

Normally, bacteria could only produce a certain amount of butanol, 15 grams of the chemical for every liter of water in the tank, before the tank would become too toxic for the bacteria to survive, said Shang-Tian Yang, professor of chemical and biomolecular engineering at Ohio State University.

Yang, however, developed a mutant strain of the bacterium Clostridium beijerinckii in a bioreactor containing bundles of polyester fibers. In that environment, the mutant bacteria produced up to 30 grams of butanol per liter.

Right now, butanol mainly sees use as a solvent or in industrial processes that make other chemicals. But experts believe this form of alcohol holds potential as a biofuel.

Once developed as a fuel, butanol could potentially work in conventional automobiles in place of gasoline, while producing more energy than ethanol.

Yang said this use of his patented fibrous-bed bioreactor would ultimately save money.

“Today, the recovery and purification of butanol account for about 40% of the total production cost,” said Yang. “Because we are able to create butanol at higher concentrations, we believe we can lower those recovery and purification costs and make biofuel production more economical.”

Currently, a gallon of butanol costs $3, just a bit more than the current price for a gallon of gasoline.

The engineers are applying for a patent on the mutant bacterium and the butanol production methodology, and they will work with industry to develop the technology.

For related information, go to www.isa.org/manufacturing_automation.