Biofuels from algae hold potential, but more work required to realize that potential

is very dependent on which technology components you combine and how you combine them to constitute a biofuel production pathway that is both environmentally sustainable and economically viable,” he explained.

Most of the current development involves growing selected strains of algae in open ponds or closed photobioreactors using various water sources, collecting and extracting the oil from algae or collecting fuel precursors secreted by algae, and then processing the oil into fuel.

“Our report brings awareness to address the concerns of making production not only commercially viable but environmentally sustainable,” he said. “In my opinion, you can’t divorce the two. As a matter of fact, most efforts aiming at lowering the production costs is to make the process more sustainable in terms of energy, water and nutrient use.”

The release notes that several researchers at the UA are exploring innovative ways to extract biofuel from algae more effectively and, ultimately, sustainably.    

For example, researchers in Cuello’s lab have developed the Accordion photobioreactor to provide a controlled environment for growing algae.

Kimberly Ogden of the department of chemical and environmental engineering studies algae better to understand the chemical structure of the oils, with the goal of being able to process them into biodiesel with the same facilities currently used to process petroleum.

Another approach, followed by Judith Brown in the UA department of plant sciences, seeks to coax algae into producing more oil.

To produce 10 billion gallons of algal biofuels, 6 million to 15 million metric tons of nitrogen and 1 million to 2 million metric tons of phosphorus would be needed each year if the nutrients are not recycled, the report says. These requirements represent 44 percent to 107 percent of the total nitrogen use and 20 percent to 51 percent of the total phosphorus use in the United States.

“The most effective way of addressing the challenges our report identified would be in an integrative approach addressing all the factors together – water, nutrients, energy, land use and greenhouse-gas emissions,” Cuello said.

“There is the biological component – the algae, and the engineering aspect — cultivating, harvesting and processing “ he added, “and there has to be a conversation between the two. For example, you could have high-yielding algae that excrete the oil or its precursor, which would eliminate the need for harvesting the algae biomass in the first place.”

Similarly, by using wastewater from agricultural or municipal sources to grow and feed the algae, one could address both the water and the nutrient issue, and lower the energy demands in the process as well.

Cuello pointed out that the report should not come as a surprise to experts. “All of the federally funded research projects on algal biofuels are, at least indirectly, already working to address these concerns that we identified and explicitly stated because people have been aware of these challenges — though perhaps not with the degree of process integration that is required.”