ASU Now | November 7, 2018
The U.S. Department of Energy has announced 36 projects that together have been awarded $80 million to support early-stage bioenergy research and development. Two ASU research teams are among the grantees, with the grants to ASU totaling about $4.5 million.
The two teams are headed by sustainability scientists in the Julie Ann Wrigley Global Institute of Sustainability: Willem Vermaas, foundation professor in the School of Life Sciences and a member of the Center for Bioenergy and Photosynthesis, and Bruce Rittmann, director of Biodesign Swette Center for Environmental Biotechnology and regents’ professor in the School of Sustainable Engineering and the Built Environment.
The DOE is investing $80 million to reduce the cost of algae-based, drop-in fuels to $3 per gallon by 2022, providing consumers with affordable, reliable transportation energy choices.
“The selections announced today highlight some of the most innovative and advanced bioenergy technologies that have the potential to produce new sources of reliable and affordable energy for American families and businesses,” U.S. Secretary of Energy Rick Perry said. “Developing all of our domestic energy resources is critical to keeping our nation prosperous and secure.”
Both ASU projects are developing innovative approaches for improving the efficiency of microalgae to capture waste carbon dioxide and convert it into transportation fuels like biodiesel. Sustainable products like healthy animal feeds, nutritional supplements and green chemicals can also be produced in this manner.
“Carbon dioxide is the costliest feedstock for cultivating microalgae, so it is imperative that we deliver it at a high efficiency to help bring down overall production costs,” Rittmann said.
Rittmann was awarded about $2 million to explore ways to make carbon dioxide delivery to algae more efficient. Traditional methods involve sparging (bubbling) carbon dioxide within the liquid used to grow the algae, which releases about 60-80 percent of the carbon dioxide back into the atmosphere. This wasteful process defeats a major goal of using microalgae to remove this greenhouse gas from the atmosphere and decreases cost efficiency.
Rittmann and his team developed a process called membrane carbonation, which uses inexpensive plastic fibers to deliver the carbon dioxide directly to the microalgae.
Vermaas and his team were awarded $2.5 million to pursue an innovative multipronged approach toward improved carbon dioxide utilization.
One approach is to increase the solubility of carbon dioxide in growth medium by developing a nanobubble gas delivery system, a project in partnership with Nano Gas Technologies, which is located in the Chicago area. Unlike the large bubbles created by sparging, which wastes most of the carbon dioxide, nanobubbles are very stable, delivering more carbon dioxide to the liquid before reaching the surface.
A second approach is to utilize amines in the medium, which greatly enhance the solubility of carbon dioxide, allowing the gas to be taken up by photosynthetic microbes for producing biofuel.
The Vermaas team is also adapting the inner workings of the photosynthetic microbe, the cyanobacterium Synechocystis, by means of metabolic engineering. Specifically, the team is engineering the bicarbonate transport proteins to improve the cellular uptake of dissolved inorganic carbon.
Both Vermaas and Rittmann are affiliated with ASU’s LightWorks, an organization that seeks to revolutionize how energy is conceptualized, produced and used. The researchers focus on discovery and design of energy systems that convert sunlight into useful and sustainable products.