by Jim Lane (Biofuels Digest) In what might become the most transformative development in fermentation yields since Noah debuted winemaking technology in the Book of Genesis, US-based White Dog Labs have unveiled a new process that eliminates the emission of CO2, a potent greenhouse gas, during fermentation and instead shifts the carbon to added ethanol production, boosting fermentation yields by around 50 percent. The by-products are distillers grains, corn oil (if extracted from the grains) and water.
According to White Dog’s management, the process can boost yields “50-100% for virtually any biochemical” in some cases with a White Dog enhanced production organism — at the high end of yield improvement, via the organism and an addition of hydrogen to the process.
Some yield jumps are even more exotic than those achieved with ethanol. For example, the process can boost acetone production by 60%, and cut CO2 by-production in half. With added hydrogen, the process can realize 120% increases in acetone production compared to conventional methods, with zero CO2 by-production.
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Comparing the results to yeast, which consumes sugar and converts half of it to ethanol and emits the other half as CO2, this organism is capable of consuming the CO2 it initially produces.
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The company has a biochemicals pathway based on the production of acetone and isopropyl alcohol (IPA), with a first commercial plant (75 kilotons per year) on the docket for 2020.
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Does it work with other sugars — for example, cellulosic? Sure can. C5s as well as C6 sugars.
How? OK, the basic idea on the ethanol side is this.
Conventional ethanol makes two moles of ethanol and two of CO2 from a mole of sugar. For chemistry buffs, it looks like this:
C6H12O6 —> 2 (C2H5OH) + 2 (CO2)
A process that eliminates the CO2 could look like this:
C6H12O6 + 6H2 —> 3 (C2H5OH) + 3 (H2O)
Where do you get the hydrogen?
OK, so here are the tough parts of the math. Prices for hydrogen are all over the map, depending on the scale of production and how you make it. We’ve seen prices at $1/kg and prices at $10/kg, quoted by various sources. As you see here, the process needs about 0.9 kilos per bushel of corn in added hydrogen.
If you’ve done your pencil work and thought, “hey, I’m paying as much as $9.00 for 1.4 more gallons of ethanol,” that’s not sustainable. In the $1 per kilo range, it’s a no-brainer — but there could be greenhouse gas consequences if the source of the hydrogen is steam reformation of methane and the leftover carbon monoxide is converted to CO2 and emitted.
So, there are some trade-offs to investigate.
One of them is producing hydrogen from lignin, and more about that here.
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We have an 8-Slide guide to White Dog Labs, here. READ MORE and MORE (Forbes) and MORE (Ethanol Producer Magazine)