Thursday, August 11, 2011

Clever Reversal of Natural Cycle Yields Rapid Synthesis

"Rather than going with the process nature uses to build fatty acids, we reversed the process that it uses to break them apart," Gonzalez said. "It's definitely unconventional, but it makes sense because the routes nature has selected to build fatty acids are very inefficient compared with the reversal of the route it uses to break them apart."

The beta oxidation process is one of biology's most fundamental, Gonzalez said. Species ranging from single-celled bacteria to human beings use beta oxidation to break down fatty acids and generate energy.

In the Nature study, Gonzalez's team reversed the beta oxidation cycle by selectively manipulating about a dozen genes in the bacteria Escherichia coli. They also showed that selective manipulations of particular genes could be used to produce fatty acids of particular lengths, including long-chain molecules like stearic acid and palmitic acid, which have chains of more than a dozen carbon atoms.

"This is not a one-trick pony," Gonzalez said. "We can make many kinds of specialized molecules for many different markets. We can also do this in any organism. Some producers prefer to use industrial organisms other than E. coli, like algae or yeast. _Physorg
Nature abstract Reversed B Oxidation Cycle

Researchers at Rice University have engineered E. Coli bacteria to synthesise bio-butanol using a clever reversal of the natural beta oxidation cycle for fatty acids. By running oxidation enzymes in the reverse direction, the researchers achieved a far more rapid synthesis than was achievable from the normal fatty acid synthesis pathway.
In a biotechnological tour de force, Rice University engineering researchers this week unveiled a new method for rapidly converting simple glucose into biofuels and petrochemical substitutes. In a paper published online in Nature, Rice's team described how it reversed one of the most efficient of all metabolic pathways -- the beta oxidation cycle -- to engineer bacteria that produce biofuel at a breakneck pace.

...Just how fast are Rice's single-celled chemical factories? On a cell-per-cell basis, the bacteria produced the butanol, a biofuel that can be substituted for gasoline in most engines, about 10 times faster than any previously reported organism.

"That's really not even a fair comparison because the other organisms used an expensive, enriched feedstock, and we used the cheapest thing you can imagine, just glucose and mineral salts," said Ramon Gonzalez, associate professor of chemical and biomolecular engineering at Rice and lead co-author of the Nature study. _Physorg
Abstract from Nature

In other bioenergy news, the US DOE has released an updated Billion Ton report on biomass production for fuels. The updated report reaffirms the potential to replace up to 30% (or more) of the US petroleum consumption, using energy and fuels from biomass. The report also describes the best environmental approaches to biomass energy production, which could result in environmental benefits overall.

Once a bioenergy infrastructure has been built, it will be possible for the machinery of bioenergy to run on its own produced energy and fuels.

Microbes such as E. Coli tend to continue dividing as long as conditions allow them to do so. If you think of microbes as reproducing factories of high value products, you may begin to realise that as long as you feed them, provide the proper environment, and carry away their waste -- high value chemicals and fuels -- these little factories will keep producing.

Biomass itself will soon be the cheapest source for sugars, to feed the microbial factories. Other biomass will be used to produce chemicals and fuels via thermochemical methods. Some will be torrefied and mixed with coal, or gasified and the syngas burned with natural gas or by itself -- to produce combined heat and power.

The bottom line is that no scientist, engineer, or agriculturalist has any idea how much biomass the Earth can produce, when given the chance. Micro and macro algae appear to be the highest yielding crops -- capable of growing on over 80% of the planet's surface. But high yielding terrestrial biomass crops are being cooked up every day, along with the means of turning the biomass into sugars. And the microbes -- the microbes are getting a lot more sophisticated in terms of synthesis speed and yields.

As long as we understand that all of these converging efforts are in the pipeline, and should not be expected to replace petroleum right away, things will come together in time.

In the meantime we are floating in hydrocarbons. Time to get away from the dieoff.orgiasts and the carbon hysterics and set to work building a civilisation that feels at home in the larger universe.

Labels: , , ,


Post a Comment

Subscribe to Post Comments [Atom]

<< Home

Newer Posts Older Posts