Tasty Energy Treats You Can Make From Brownies
by Jim Lane (Biofuels Digest) Terpenes may be the most unloved class of energy molecule of all time, if you compare R&D spending to potential. Even ARPA-E, the home of high-risk, high-reward government research into energy, hasn’t delved into terpenes since 2012’s OPEN invite, where Allylix picked up a single $467,6905 award to develop a “Renewable Platform for Production of Sesquiterpene Aviation Fuels & Fuel Additives from Renewable Feedstocks”. Then, Allylix was acquired by Evolva, which has focused its portfolio on stevia, resveratrol and nootkatone and put terpene fuel capabilities on the back burner.
Allylix was making super-dense fuels that could serve as high-energy additives, or ultimately serve the JP-10 market — think $25 per gallon missile fuel. One problem? The feedstock was sugar, which started the process with a cost albatross around its neck.
But what about isoprene? At the end of the day, two isoprene molecules make up a terpene and three make up a sesquiterpene. And there’s much to love about isoprene.
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1. Love drop-in fuels? Isoprene is a hydrocarbon, C5H8.
2. Dislike the loss in vehicle range with ethanol and EVs? Isoprene checks in at 107,000 BTUs/gallon, roughly 40% ahead of ethanol, and about 6 percent short of gasoline.
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3. A fan of high octane? Isoprene is a chart-buster, checking in with a RON of 132, compared to 109-120 for ethanol and 84-85 for standard gasoline at the refinery.
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4. One more thing to prize in isoprenes is that they also serve a higher-value chemicals market — bio-isoprene is a perfectly good material for tires — so, a project to make isoprenes has a natural high-value, small-volume market but translates well to bigger markets that large production volumes can unlock.
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If you follow the basic chemical math, you won’t make isoprene the way that organisms do, but it’s easier to get the idea:
5CO2 + 4H2O —> C5H8 + 4 O2
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As JGI points out:
Approximately 40 percent of the B. braunii cells is made up of hydrocarbons, and the oil produced can be easily converted and used for vehicle and jet fuels with more than 90 percent efficiency. B. braunii has been studied for several decades not just for its potential as a source of biofuel but for its ability to sequester carbon.
But there are other candidate microorganisms …
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The problem is, as always, an organism that makes the right concentrations of target material, but never fast enough. Back in the age of the dinosaurs, no one was on the clock, take a million years, no worries. But here we are in the 21 century and the operative word in this bioeconomy is speed. Hard to get three year payback.
So, someone has to get Brownie into the gym and work hard on productivity. And make all those lovely isoprenes. READ MORE
