Magnetic algae make biofuels sticky
By John Roach

Scientists at a government lab in New Mexico have created what appear to be magnetic algae, a breakthrough that could lower the cost of harvesting biofuels from the microscopic plants.

The trick involved transferring to algae a gene from soil bacteria that align themselves with Earth's magnetic field, explained Pulak Nath at the Department of Energy's Los Alamos National Laboratory.

"We expressed that gene in algae and it started making what we think are magnetic particles," he told me Friday. "We still have to confirm that, but we could put a magnet next to those algae and see these algae getting attracted."

Magnetism studies
Scientists have studied the soil-living so-called magnetotacic bacteria since the 1970s, primarily as a model to understand how birds are able to migrate thousands of miles each year.

"The whole idea is that they probably have some sort of compass in their brains," Nath said. As a DOE-funded scientist, he turned to those studies in search of an application to cost efficiently harvest algae for biofuels.

Current techniques for extracting algae from the ponds where they are grown include sound waves and the addition of chemicals that cause the algae to clump together, a process known as flocculation.

These techniques account for about 30 percent of the total cost of algae-based biofuel production, Nath noted, and "is one of the limiting steps for algae fuel from becoming cost competitive to fossil fuels."

Using magnets
Permanent magnets are inexpensive. In theory, algae biofuel systems could flow algae-filled water through a tank lined with the magnets and the algae will get separated from the water, Nath explained.

"And that won't cost us any money in terms of energy input because we are using these permanent magnets and the energy from these permanent magnets — other than the material — is free," he said.

The research, he cautioned, is in the early stages. So far, they've created one species of magnetic algae. Going forward, they will try to transfer the gene to more candidates for algae biofuel production.

The lab's ultimate goal, Nath said, is to take the technique to the proof-of-concept stage and then have someone else "take this technology and take it forward."

To take the research forward, there is incentive in the government push to derive 36 billion gallons a year from a mix of biofuels by the year 2022.

Other factors that must be tackled for the efficient scale-up of algae biofuels include ways to reduce their need for massive amounts of water and land.

Nothing too major in of itself but I couldn't help thinking how this general train of development might make aquaculture and aquaponics more efficient and economical attractive... beyond simply making biomass perhaps easy to collect... which might be good for biofuels but also possibly for algae-based water filtration or a number of other uses.