Home brewers know that fermentation stops when the yeast produce so much alcohol they can no longer survive. If you want a higher alcohol content, you'd better find a different yeast strain that can survive in a more toxic soup.
That, in essence, is what Ohio State University researchers have done in developing a new strain of bacterium (clostridium beijerinckii) that produces twice the amount of alcohol -- in this case butanol -- before kicking the bucket. The potential payoff is a motor fuel that has many advantages over ethanol -- America's current biofuel of choice.
Shang-Tian Yang, professor of chemical and biomolecular engineering, says butanol, which is used widely as a solvent, now sells for $3.50 to $5 a gallon. Because much of the cost is in production, getting twice the amount of butanol from the same amount of bacteria could reduce the cost by half.
"Ethanol has severe limits," Yang says. "It is corrosive and can't be shipped through a pipeline, you have to ship using trucks. And it must be mixed with gasoline to be used as a fuel in current automobiles."
He says ethanol alone has around a third less energy content than gasoline and gets only 65 percent of the mileage. It is highly volatile and explosive. Yang says butanol is superior to ethanol in every way but one: its price.
Boosted by a $1-million grant from the Ohio Third Frontier, Yang is leading work to develop the technology needed for commercial production. In the meantime, his team has applied for a patent on the new bacterium and production process.
Source: Shang-Tian Yang, Ohio State University
Writer: Gene Monteith