Tulane has applied for a patent for a method to produce the biofuel butanol from organic material, a process developed by associate professor David Mullin, right, postdoctoral fellow Harshad Velankar, center, and undergraduate student Hailee Rask.

By John Roach, contributing writer at msnbc.com.

The Internet is delivering a slow death to newspapers, but many of us still have piles of the stuff around the house that a microbe called TU-103 will convert to butanol, a biofuel that is nearly as energy dense as unleaded gasoline.

"This is a bacterium that we isolated straight out of nature," David Mullin, a cell and molecular biologist at Tulane University in New Orleans, told me today.

In fact, it was isolated from a truckload of feces he and colleagues collected from grass-eating animals at the Audubon Zoo in New Orleans, figuring their intestinal tracts likely harbored a naturally occurring microbe that had the qualities they sought.

They were looking for a microbe that produces butanol from cellulose — a woody, fibrous material in plants — rather than more expensive sugars and starches, as well as one that does this in the presence of oxygen.

All other known naturally-occurring butanol-producing microbes do so in the absence of oxygen — that is, oxygen kills them, which makes growing them, transporting them, and working with them rather tedious, Mullin noted.

"Among the many butanol-producing strains that we managed to isolate, we found one that can grow in the presence of air and expresses a cellulase (an enzyme) that can use cellulose to make butanol," he said.

The microbe is a strain of Clostriudium called TU-103. To prove it can convert cellulose to butanol, they wet, shredded and blended a bunch of newspaper (which is essentially cellulose) into a soupy stew and then added in the bacteria. "They started making butanol from newspaper," Mullin said.

The natural advantage
Other strains of Clostridium have been genetically engineered to produce butanol from cellulose, as have strains of E. coli. Mullin doesn't yet know how well TU-103 stacks up against these genetically engineered microbes, but said finding one that produces butanol efficiently in nature is likely an advantage.

"This stuff has been worked out by natural selection, by nature, not the human mind," he said. "[We are] starting with an organism that already does something really efficiently; we don't have to pull in genes from other bacteria and figure out how to get them expressed."

However, TU-103 could see some genetic enhancements down the line. Mullin's team is sequencing the genome and identifying the genes responsible for producing butanol from cellulose in the presence of oxygen. The team could then increase the activity of those genes to make the microbe more efficient.

Green fuel
Research teams are racing to scale up the economically-efficient production of butanol, as it's widely considered a superior alternative to other biofuels, such as ethanol.

"If you drain the gasoline out of your gas tank and replace it with butanol, you can start your engine," Mullin said. "If you add ethanol to your fuel tank, no matter how many times you turn the key, it would never turn over; it doesn't have enough energy to run your engine."

That's why ethanol is blended with gasoline, usually up to about 10 percent, and not pumped straight into the gas tank, he added. What's more, most ethanol today is produced from corn and other food crops, which is a morally sticky proposition in world that routinely struggles with food shortages.

Mullin said he's shown that TU-103 converts seedy cotton that would otherwise go to waste into butanol and will soon try it on bagass, a fibrous material leftover from a sugarcane processing plant in Louisiana.

Newspapers, he noted, were a proof of concept — "something people can easily get their hands on and that they can easily wrap their minds around."

At least until the Internet kills newspapers altogether.

source: futureoftech.msnbc.msn


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