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Missouri reseachers work to make algae a viable energy option

Researchers in Missouri are looking at various methods to reduce the costs of growing algae on a large scale and extracting the plants' oil.
Researchers in Missouri are looking at various methods to reduce the costs of growing algae on a large scale and extracting the plants' oil.

By Catherine Wolf, KWMU


St. Louis, MO –

Most people only see green sludge when they look at algae, but some scientists think the oil in the plants could provide a partial solution to the country's energy needs. Oil from algae can be converted into biodiesel, but algae haven't been used on a wide scale to make fuel because of high production costs.

On a recent day, scientist Dick Sayre strolled through a room containing tubes of green algae at the Donald Danforth Plant Science Center in St. Louis and explained why it isn't just sludge. Sayre is one of hundreds of researchers nationwide working on developing the plants as a source of oil for biodiesel. He said certain strains could produce 10 to 30 times more fuel per acre than crops like soybeans.

"They have the advantage of higher productivity, harvesting every day of the year and, also importantly, we are able to harvest 100 percent of the biomass. That is not generally the case for terrestrial crop systems," Sayre said.

Converting the oil from algae into biodiesel isn't a new idea. The U.S. Department of Energy spent nearly 20 years researching it, but abandoned the project in 1996 saying large scale production wasn't economically feasible.

Sayre said he's found a way to get around one of the cost challenges.

Standard procedures to remove oil from algae take several steps of binding the algae together, drying it and then extracting its oil. Instead, Sayre is mixing organic solvents with the algae while they're still in water. He said the solvents cause oil to separate from the plants without killing them, and no energy or money is spent to remove algae from water or dry the plants.

"It's one of the economic drivers we think will reduce the current cost of producing oil from algae, which is about $30 per gallon down to about $3.50 per gallon," Sayre said.

While Sayre works in the high-tech plant science center in St. Louis, a professor of mining engineering toils in the lower level of his office building in Rolla. Missouri University of Science and Technology Professor David Summers said it may sound like a pie-in-the-sky idea, but he thinks growing algae in abandoned mines could be an economical way to raise the plants. Summers said it would cut down on start-up costs by using existing space, and algae could be grown in states like Missouri year-round because temperatures could be kept constant underground.

Summers plans to use LED lights instead of sunshine to nourish the plants. He said he's even working on a way to trick the algae into reproducing more often by flicking the lights on and off.

"I'm afraid algae aren't that smart, you see. They don't really understand that days have to be 24 hours long. We can shrink their day until it's less than a second. And so by shortening the day, we can actually get this higher growth rate and our production goes up significantly," Summers said.

To date, the researcher hasn't grown any algae in mines, but said he's had success in a mine-like environment his assistant built with discarded theater curtains.

David Brune, a professor of bio-energy engineering at the University of Missouri in Columbia, has worked with algae for 30 years. He said he is skeptical of the practical applications of some research.

"They get these very high levels of production or density in a small flask on a small scale and then they take that and multiply that by some number and say they can get very large productions in the field. It's just that that has never been demonstrated. It remains basically laboratory speculation," Brune said.

Brune said until a researcher is able to take a project from the lab to the field, the footrace to develop cost-efficient ways of growing and processing algae will continue. He said it could be a decade or longer before algae are being widely farmed for biodiesel production.

In the meantime, Brune said the plants can be put to plenty of other uses like feed for fish, removing water pollutants, and as an ingredient in dietary supplements.