Published on March 31st, 2014 | by James Ayre1
High-Energy Biofuel For Rockets, Missiles, And Other Aerospace Applications, Via Engineered Bacteria
March 31st, 2014 by James Ayre
A high-energy biofuel — potentially capable of replacing or supplementing expensive missile fuels, such as JP10 — has been created via the use of a genetically engineered bacterium by researchers at the Georgia Institute of Technology and the Joint BioEnergy Institute.
For those wondering, the hydrocarbon in question, pinene, is actually exactly what it sounds like, a chemical produced by trees (especially pine trees). Kind of funny when you think about it — rockets powered by a chemical used by trees to repel insects produced by bacteria genetically engineered by humans. :/
Improvements to the process are still necessary in order for it to become economically viable (production boosted 26-fold), but given the great value placed on high-energy fuels by governments/militaries/etc, it’s very likely that we’ll hear more about this in the relatively near future.
The researchers also note the interesting fact that the biofuel could potentially help “facilitate (the) development of a new generation of more powerful engines.” Hmmm…
The Georgia Institute of Technology provides more:
By inserting enzymes from trees into the bacterium, first author and Georgia Tech graduate student Stephen Sarria, working under the guidance of assistant professor Pamela Peralta-Yahya, boosted pinene production six-fold over earlier bioengineering efforts. Though a more dramatic improvement will be needed before pinene dimers can compete with petroleum-based JP-10, the scientists believe they have identified the major obstacles that must be overcome to reach that goal.
“We have made a sustainable precursor to a tactical fuel with a high energy density,” stated Peralta-Yahya, an assistant professor in the School of Chemistry and Biochemistry and the School of Chemical and Biomolecular Engineering at Georgia Tech. “We are concentrating on making a ‘drop-in’ fuel that looks just like what is being produced from petroleum and can fit into existing distribution systems.”
Given the fact that JP-10 is itself a very limited fuel — only so much can be extracted from any single barrel of oil — the potential for it to be replaced by a (relatively) expensive biofuel is much greater than it is for something like gasoline. JP-10 currently sells for around $25 per gallon.
“If you are trying to make an alternative to gasoline, you are competing against $3 per gallon,” Peralta-Yahya continued. “That requires a long optimization process. Our process will be competitive with $25 per gallon in a much shorter time.”
More information on the research process:
Peralta-Yahya and collaborators set out to improve on previous efforts by studying alternative enzymes that could be inserted into the E. coli bacterium. They settled on two classes of enzymes — three pinene synthases (PS) and three geranyl diphosphate synthases (GPPS) — and experimented to see which combinations produced the best results.
Their results were much better than earlier efforts, but the researchers were puzzled because for a different hydrocarbon, similar enzymes produced more fuel per liter. So they tried an additional step to improve their efficiency. They placed the two enzymes adjacent to one another in the E. coli cells, ensuring that molecules produced by one enzyme would immediately contact the other. That boosted their production to 32 milligrams per liter — much better than earlier efforts, but still not competitive with petroleum-based JP-10. Peralta-Yahya believes the problem now lies with built-in process inhibitions that will be more challenging to address.
“We found that the enzyme was being inhibited by the substrate, and that the inhibition was concentration-dependent,” she explained. “Now we need either an enzyme that is not inhibited at high substrate concentrations, or we need a pathway that is able to maintain low substrate concentrations throughout the run. Both of these are difficult, but not insurmountable, problems.”
“Even though we are still in the milligrams per liter level, because the product we are trying to make is so much more expensive than diesel or gasoline means that we are relatively closer.”