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Researchers use bacteria to produce potential gasoline replacement directly from cellulose


March 10, 2011

Researchers have succeeded in producing isobutanol directly from cellulosic plant matter such as corn stover (Image: mattdente via flickr)

Researchers have succeeded in producing isobutanol directly from cellulosic plant matter such as corn stover (Image: mattdente via flickr)

With the situation in Libya causing a spike in fuel prices worldwide there's some good biofuel-related news out of the U.S. Department of Energy's BioEnergy Science Center (BESC) that could help to reduce many countries' dependence on oil imports. For the first time, BESC researchers have succeeded in producing isobutanol directly from cellulosic plant matter using bacteria. Being a higher grade of alcohol than ethanol, isobutanol holds particular promise as a gasoline replacement as it can be burned in regular car engines with a heat value similar to gasoline.

Due in large part to its natural defenses to being chemically dismantled, cellulosic biomass like corn stover and switchgrass, which is abundant and cheap, has been much more difficult to utilize than corn or sugar cane. This means that producing biofuel from such biomass involves several steps, which is more costly than a process that combines biomass utilization and the fermentation of sugars to biofuel into a single process.

Building on earlier work at UCLA in creating a synthetic pathway for isobutanol production, the BESC researchers managed to achieve such a single-step process by developing a strain of Clostridium cellulolyticum, a native cellulose-degrading microbe that could synthesize isobutanol directly from cellulose.

"In nature, no microorganisms have been identified that possess all of the characteristics necessary for the ideal consolidated bioprocessing strain, so we knew we had to genetically engineer a strain for this purpose," said Yongchao Li of Oak Ridge National Laboratory.

The research team chose Clostridium cellulolyticum, which was originally isolated from decayed grass, because it has been genetically engineered to improve ethanol production, which has led to additional more detailed research. While some Clostridium species produce butanol and others digest cellulose, none produce isobutanol, an isomer of butanol.

"Unlike ethanol, isobutanol can be blended at any ratio with gasoline and should eliminate the need for dedicated infrastructure in tanks or vehicles," said James Liao, chancellor's professor and vice chair of Chemical and Biomolecular Engineering at the UCLA Henry Samueli School of Engineering and Applied Science and leader of the research team. "Plus, it may be possible to use isobutanol directly in current engines without modification."

Earlier this week, U.S. Energy Secretary Steven Chu visited the BESC to congratulate the research team, saying, "Today's announcement is yet another sign of the rapid progress we are making in developing the next generation of biofuels that can help reduce our oil dependence. This is a perfect example of the promising opportunity we have to create a major new industry – one based on bio-material such as wheat and rice straw, corn stover, lumber wastes, and plants specifically developed for bio-fuel production that require far less fertilizer and other energy inputs."

The team's work is published online in Applied and Environmental Microbiology.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Now we have a US concept similar to the British one on Gizmag not long ago. Will this ever be put into practice or will we have to wait for domed cities,cure for cancer,etc.?

Why has it taken us over a hundred years to find a burning liquid to replace gasoline and diesel? (other than greed and apathy,of course...)


Right on Griffin. Big thumbs up on that one d;-)


I have been touting the benifits of cellulose isobutanol derived from Industrial Hemp for quite a few years now.... Corn is not the answer. Corn can only grow in certain climates. Hemp can grow almost anywhere and has a higher cellulose content. The reason for the push with corn is that big Industrial Agriculture companies have spent sooooo much money on genetically modifying corn that they now have to recoup their expenditures. I repeat: Corn is not the answer!

Rob Robinson

I am a retired research chemist and followed research in fuels since 1980. My work indicates all the oil imported into the US could be replaced with methanol. Current list price methanol is $1.28 per gallon. It takes about 1.5 gallons methanol to replace one gallon of gasoline. Methanol can be made in the US with domestic feed stocks. Methanol can be made from biomass, coal and natural gas. New methanol plants and a new methanol industry would produce thousands of new high paying jobs and methanol is environmentally clean.

China uses billions of gallons of methanol to replace gasoline. Americans are upset over gasoline prices while China is building methanol plants. To replace gasoline with methanol is a big thing. It is not something that can be done on a small scale and it would require a national effort. Oil companies will not play fair or be passive if a large share of their market is replaced with a new fuel.

Today is a sad day for America. The country that ruled the last century and put a man on the moon can not manufacture a car fuel. In past times Americans would dream big and replacing gasoline is big. China is capable of making the dream happen. The Chinese are doing the hard thing and the smart thing. Americans are acting weak, clueless and helpless.

We can not blame the bozos in Washington for high gas prices. The rich white guys we send to Washington and Nashville do whatever the voters desire. We elect them even when they act weak, clueless and helpless.

Maybe the best way to sum up the real problem with gasoline prices is to say, \"We have met the enemy and the enemy is us.\"

Mike Dyer Cleveland TN

Mike Dyer

Making isobutanol from corn stalks and leaves instead of ethanol from corn kernels is switching from burning food for humans to burning food for cattle.

Hemp and any other non-food organic material that can be used to make isobutanol would be a better choice. Using food (from any part of the food supply chain) to make fuel is just plain stupid because it makes food more expensive.

Facebook User

Rob Robinson, corn also provides grain for human and livestock consumption. It\'s something that has to be grown anyway and the stover is just going to waste right now. That\'s half of the plant not used for anything at all, just left to rot in the fields. Why not put it to use?


Hemp has so many industrial uses it staggers the mind . . but it is illegal to grow in many states . .


\"Hemp\" legalization is a completely irrational, politically charged issue. Corn stover is not, therefore corn stover will be used.

The political climate in the US during the past 30 years proves that nothing about politics is rational, logical, or makes any kind of economic sense. The political \"right\" clamors about the budget deficit, but the last two administrations to actually balance the budget were \"left,\" Democratic (Johnson, Clinton) while the last two with out-of-control deficits were \"right\" Republican (Reagan, Bush 43). Legalizing hemp production and/or processing for any purpose would require a massive bipartisan legislative effort, and it \"ain\'t happening\" in my lifetime.

William Lanteigne

another advantage of butanol over ethanol is it doesn\'t attract water , thus avoiding the phase separation that effects our current gasoline. As an avid American Musclecar fan and owner, this makes me happy to know my tank and lines may not be subjected to rust and corrosion.


Really??? What a joke you should be to embarrassed to print this garbage. HEMP!!!


I remember reading about this before. The article concluded that if the bacteria get out of the lab we will stand in two feet of gasoline replacement and not a single plant will survive on earth.


Genetic engineering, it feels so good to be God!

Chris Mentzel

To Chris Mentzel, what article are you referring to \"link\"? Sounds like the same kind of article that told of university students grinding up cheap 5mm LEDs and then telling everyone how many toxins were in LEDs.

jason 77

Needed soon if gas prices hit above 5.00/

Stephen Russell

I take exception with the idea that corn stalks are used as cattle feed, usually they are not since they do not have enough food value.

Michael Hertel

Field corn for cattle feed is chopped up, stalks, leaves and ears, as it stands in the field.

There are corn choppers designed specifically for that process. They blow the chopped up corn into trucks which haul it either to a silage pit or to a machine that blows it into a large and long plastic bag.

It's left to ferment a while before being scooped out to be fed to the cattle. The fermentation partially breaks down the chopped up stalks and leaves, which increases the amount of food value for the cattle.

Stalks from sweet corn are generally not used for cattle feed since they don't ferment well without the sugars from the corn kernels.

Unprocessed corn is actually a pretty poor food for humans, even though it tastes good. (Corn dump, or "Corn? When did I eat corn?") Omnivore digestion is not as efficient at breaking down some types of vegetable material, then converting or extracting the compounds their physiology requires.

Processing corn with alkali (Google that) is a many centuries old process, used to produce hominy, corn meal and other products. It partially breaks down the tough cellular structure of the corn kernels so our digestive system can access the usable compounds.

Corn on the cob, canned corn or other whole kernel corn product tastes good but you aren't getting much nutrition out of it.

Herbivore digestion and biochemistry can do a much better job of breaking down plant material, extracting and converting the chemical compounds it requires. Quite a bit of that process comes from their long and complex digestive systems, including regurgitating and "chewing cud" to add more saliva to the mix.

The way biology works intermeshes so that the vital compounds omnivore and carnivore biology cannot extract or convert from plant material is stored in the tissues of herbivores.

Gregg Eshelman
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