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  (Source: ksj.mit.edu)
E. coli was used to make fatty acids of the correct length

A biofuel that acts similar to gasoline minus the carbon dioxide seems like an ideal solution to staying green, keeping current vehicles relevant and the dwindling oil supply -- and researchers may have found the first steps toward that direction. 

Harvard University researchers -- led by Pamela Silver, Ph.D., a Wyss Institute Core Faculty member and Professor of Systems Biology at Harvard Medical School -- have engineered bacteria to make precursors of high-octane biofuels to potentially replace gasoline. 

The problem with gasoline is that its oil supply is running low, and gives off large amounts of carbon dioxide. But gasoline isn't all bad -- it can produce a lot of energy when burned in an internal combustion engine, and it stays in a liquid form no matter the temperature. 

This is where many of today's biofuels go wrong. They nix the carbon dioxide, but can't produce the power that gas can in an internal combustion engine. In fact, they produce only two-thirds of the energy gasoline can. Also, ethanol-packed fuels can corrode pipes and tanks normally used for gasoline. Between these two reasons, biofuel use would make a majority of today's vehicles (with internal combustion engines) irrelevant. 

That's where Harvard's new study comes in. Using E. coli to make fatty acids, which are gasoline precursors, the team ended up with energetic molecules of carbon and hydrogen atoms. These chains were about 4-12 carbons long, because anything shorter wouldn't pack enough energy for fuels and anything longer would be "waxy." Oil refineries make medium-length chains too, but use petroleum while this study used living organisms. 

The team then adjusted a metabolic pathway for E. coli that creates fatty acids. The pathway allows carbon from sugar to flow, and as it flows, it grows longer. It eventually leaves as a long-chain fatty acid. They then genetically altered an enzyme that typically allows for long-chain fatty acids so that it would only allow eight-carbon chains.

They also tried blocking the flow of carbons using a drug that blocks certain enzymes, which are responsible for extending fatty acid chains. This caused medium-length chains (which the team wanted) to pool up behind the barrier. But some of the carbons could still pass by to build membranes. 
In the end, the team mass-produced an eight-carbon fatty acid called octanoate. This can be converted into octane.

This study was published in Proceedings of the National Academy of Sciences.

Source: Eurekalert



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RE: Hmmmm.....
By Amiga500 on 6/27/2013 4:21:17 AM , Rating: 3
:-)

Get some gasoline, stick it into an open tray and leave it outside for a few hours.

Come back and tell me how much is left.

Gasoline is a liquid because it is easily contained, which means the partial pressure of gasoline vapour can reach saturation point in the container ullage quite quickly, preventing further evaporation. Without that restricted ullage, it would continue to evaporate until there would be no liquid left (or the partial pressure of fuel vapour in the entire atmosphere reached saturation point...).


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