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Researchers Use Ultrasonics to Boost Yield of Corn Ethanol Production

Researchers at Iowa State University are exploring the use of ultrasonics to boost ethanol production from corn. The team pre-treated milled corn to break the corn pieces into fine particles, thereby exposing more of the corn’s starch to the enzymes that convert starch to sugars.

Preliminary tests have increased the corn’s release rates of sugars by nearly 30%, promising a greater ultimate ethanol yield per bushel. The research team also plans to see if ultrasonics release some sugars from the fibrous, cellulosic material in corn.

Ultrasound pretreatment generates cavitation in the corn slurry, resulting in strong hydrodynamic shear forces. The shear forces help disintegrate the corn slurry into fine particles, thereby exposing the much larger surface area to enzymatic activity during liquefaction / saccharification.

Not only can the ultrasonic pretreatment facilitate more complete starch conversion, consequently improving the overall ethanol yield, but it could also reduce the total amount of enzymes and nutrient needed, and the processing time.

Preliminary test data showed that the pretreatment resulted in nearly a 50-fold reduction in corn particle size during 40 seconds of sonication, producing the 30% increase in sugar yield. With the advancement in ultrasonic technology in recent years, the energy conversion efficiency of ultrasonic units has improved to > 90%.

This seems to work very well. We’re releasing more of the corn’s stored energy in a shorter period of time with less energy consumption.

—David Grewell, Agricultural and Biosystems Engineering

The discovery has led to a patent application and a one-year provisional patent for immediate commercialization of the technology. Grewell is directing the research project. Samir Khanal and Hans van Leeuwen, an Iowa State professor of environmental engineering, are also working on the project. Van Leeuwen has also been leading a research effort on the use of a mold-based process for cellulosic ethanol production. (Earlier post.)

The ultrasonics research is supported by an $80,519 grant from Iowa State's share of the Grow Iowa Values Fund, the state’s economic development fund.

Grewell said the researchers’ next step will be to quantify the amount of ethanol produced when corn slurry is treated with ultrasonics. Then the process will be tested at a larger, pilot scale.




Over the past 10 years I have read a vast multitude of applications where ultrasonics were shown to improve everything from mending broken bones to (now) Ethanol production. I think the only applications I can think of that actually use ultrasonics would be ranging sensors and testing for damage in solid components.

I wonder if this will just be another whimsical idea that works but gets shelved for one reason or another.

Rafael Seidl

This ought to work for other feedstocks as well, e.g. sugar beets. Afaik, sugar cane is processed into liquid molasses anyhow.

It's unclear to me how ultrasound cavitation would convert cellulose into sugars, though. Perhaps the stover et al. contain small quantities of sugars already which are merely exposed by this mechanical process.


That's the way I like it. Also with sugerbeets are huge progresses reported: without genmanipulation +10% ethanol output, with gen expected in the nearterm + 25%. And that's only the beginning. You see, standing on a realistic fundament, we can improve output continiously. And this way is going through cellulosic ethanol as well. Companies like Novozymes, Sunopta or Genencor are working very promisly. Their products are available for immidiate use and getting better almost every month. Now we can just pray, that this price of oil is not dropping to much. Elsewere the whole research would be stopped (already happened 1981).


edf -- I agree -- if the price of oil drops too much (and I'm sure it will) then all this progress will surely come to an end -- there must be a way to tax it as it drops so there's not much pain but yet the increased rev goes to R&D.



Ben & Jerrys is using sound waves to chill their ice cream and some mining outfit in Australia is using ultrasound to process iron ore. I think this is one of those technologies that is on the cusp -- still requiring either some additional engineering, or a reliable market to justify ramp-up.

Harvey D.

Seems that this processus could be useful as pretreatment for most types of feedstock? Would it facilitate production and lower cost of cellulosic Ethanol? It could become an interesting option depending on cost and treatment time.

Lets hope that high gas price will be around long enough for similar process development to take place. A variable carbon tax could ensure that it does. Would it be acceptable to the majority of voters?


It's different now, than in 1981.

Americans who own flex-fuel vehicles will pay more, lots more, for ethanol, if they have to, so the trick is to get enough of them on the road soon. The volatility of gasoline has become tedious enough that I believe the demand curve for ethanol will rise even as gas prices go down.

Look at the premium people were willing to pay for hybrids, and they stood in line to do so.


ultrasonics is also used in oil refineries to increase yield per barrel of crude.

I neither paid a premium, nor stood in a line for my hybrid.


allen zheng

Forget corn or sugar beet; unless climate/economics do not pan out, sweet sorghum is the way to go in making alcohol (ethanol, butanol). With a far better energy balance, (1.3-1.8 for corn, ~1.9 for sugarbeet, 3.4-6.1 for sweet sorghum-better if non-irrigated, 0.817-average for petro gasoline, 8.3 for sugar cane) better gallons per acre (g/a) yields, (300-400 g/a corn, ~600 g/a sugar beets, 600-700 g/a sweet sorghum/sugar cane) and lower water usage, (10-35% less) it is a no brainer. Politics, vested interests, and inertia are the only problems.


does anyone know any applications of ultrasound taht would require the reflection coefficient at frequencies in the 20khz range to be used or known more precisely


does anyone know any applications of ultrasound taht would require the reflection coefficient at frequencies in the 20khz range to be used or known more precisely

I am student,i cant pay,but i need information about this

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