UA Researcher Predicts Algae Biofuel at the Pump in 5 Years
Research originally focused on growing algae to feed astronauts could within five years offer a readily available renewable source of fuel for our vehicles here on Earth, a University of Arizona professor believes.
In the 1960s NASA began looking at algae as a way to facilitate human habitation in space, said Joel Cuello, UA professor of agricultural and biosystems engineering. Potential space applications for algae included feeding space explorers as well as treating wastewater and regenerating carbon dioxide produced by astronauts, he said.
“Depending on the species, certain algae are rich in protein or fats or carbohydrates, so with the right mix of algae, theoretically, you could come up with a diet that is sufficient for human life,” Cuello said. “Unfortunately, astronauts did not want to eat algae.”
Algae: It's Not What's for Dinner
Cuello’s current work at the UA focuses on mass-producing algae for biofuels, so that instead of feeding astronauts the microscopic organisms can be used to produce renewable energy to power vehicles.
And using algae to produce biofuels is not taking food out of the mouths of people.
“If you use a food crop as an energy feed stock, like corn and soybeans, you are diverting them from being a food producer into being a fuel producer,” Cuello said. “When you use algae there is no conflict or competition between food and fuel, since most people don’t eat algae.”
Algae also offers more productive yield rates per area than most other feed stocks, and can be grown using treated wastewater rather than potable water needed for most other feed stocks, he said.
Different types of algae can be selected to produce a variety of biofuels. Cuello’s research team is growing and testing various types of algae to maximize hardiness, rapid growth and biofuel capabilities. Some species are up to 75 percent oil by dry weight, he said.
“In the lab we have algae species that can produce hydrocarbons that can be used for jet fuel production. There are species that accumulate fatty acids which can produce biodiesel,” he said. “Some accumulate starch which can be fermented to produce ethanol. And some species of algae directly produce hydrogen gas, which is another type of biofuel.”
While algae production is successful on a laboratory basis, the challenge today is making large-scale production of algae cheaper and commercially feasible, he said.
Green Grows the Algae
One of the largest costs for commercial algae production is the photobioreactor, a container where algae grows with the help of circulating nutrients and light.
Enter the UA’s Accordion, a photobioreactor that Cuello and his graduate student Joe Ley designed and which Cuello believes could be used to inexpensively produce the huge amounts of algae needed for an effective biofuel program. UA has been granted a provisional patent for the device, and is working for a full patent, Cuello said.
The device, named after the musical instrument because of a loose similarity in shape, flows water and nutrients through a vertical series of clear panels set at a variety of angles, allowing the mix to have a controlled flow and receive a steady dose of light needed for growth.
The key benefit is the modularity of the system, which lends itself to convenient scale up, Cuello said. Another benefit comes from the material: inexpensive polyethylene film is used rather than glass or other expensive materials to bring the cost down. The device is made from off-the-shelf items.
Ley, UA graduate student in agricultural and biosystems engineering, is working to refine a prototype Accordion located at the UA Campus Agricultural Center. He is using the Accordion to grow Botryococcus braunii, a strain of oil-rich algae with jet biofuel applications.
The mix of algae and liquid nutrients is pumped to the top of the device, where it flows down from section to section while bathed in soft fluorescent light. In a real world application, rows and columns of the Accordions could be arranged inside a greenhouse or even outdoors in open air where sunlight would be the principal source of light.
In addition to lower cost, Accordion offers other benefits, Ley said.
The polyethylene plates are transparent and relatively thin, so that the algae can obtain the greatest amount of light needed for growth.
The flow of nutrient solution is regulated to keep the microscopic algae in suspension, thus ensuring that all algae cells receive adequate nutrition and light.
And the device is mounted on a framework of PVC pipe, allowing the shape and configuration of the panels to be readily changed as needed to maximize production rates, Ley said. In a real-world setting the PVC for the framework would be replaced by a less expensive material.
Mass Production
The design is scalable, and sites featuring vertical towers of hundreds -- or thousands -- of Accordions could produce the vast amount of algae needed for high-output production of biofuels, Ley said.
“We could develop acres and acres of systems like this for the higher production needed to produce biofuels,” Ley said.
The liquid pumped through the Accordion starts clear, and 500 milliliters of algae are used to seed the process. The liquid turns green as algae grow exponentially until growth plateaus after seven to 10 days, Ley said, at which time algae growth remains steady and the material can be harvested.
In addition to improving the algae-growing technology, Cuello’s research team is working to make harvesting the algae for processing more efficient. Current methods require a centrifuge to separate the algae from the liquid nutrients, which is expensive and time consuming, Cuello said.
“We’re developing a novel harvesting mechanism that will be able to accomplish this task more economically,” he said, but declined to offer details until patents are in place to protect the new technology.
Cuello believes the day is not too far off when we will be able to fuel our vehicles with biofuels derived from algae. “I really believe we will be able to make use of algae-based biofuels, probably in two to three years,” he said. “We will have the right mix of technologies in place in two to three years, and it will be at the pump, I would say, in five years.”
In addition to biofuels, a growing number of other commercial applications exist for the UA’s algae research efforts, Cuello said.
A company in Norway, Biopharmia, is in discussions with UA to use the Accordion technology, initially to produce high-value chemicals such as human food supplements and high-end fish feed, Cuello said.
And Cuello’s lab is receiving funding from Phoenix-based Sonador Research Group to pursue research into production of algae-derived antitumor compounds that target various types of cancer.