ASU scientists bring the heat to refine renewable biofuel production

September 27, 2012

Perhaps inspired by Arizona’s blazing summers, Arizona State University scientists have developed a new method that relies on heat to improve the yield and lower the costs of high-energy biofuels production, making renewable energy production more of an everyday reality.

ASU has been at the forefront of algal research for renewable energy production. Since 2007, with support from federal, state and industry funding, ASU has spearheaded several projects that utilize photosynthetic microbes, called cyanobacteria, as a potential new source of renewable, carbon-neutral fuels. Efforts have focused on developing cyanobacteria as a feedstock for biodiesel production, as well as benchtop and large-scale photobioreactors to optimize growth and production. Roy Curtiss and Xinyao Liu Download Full Image

ASU Biodesign Institute researcher Roy Curtiss, a microbiologist who uses genetic engineering of bacteria to develop new vaccines, has adapted a similar approach to make better biofuel-producing cyanobacteria.

"We keep trying to reach ever deeper into our genetic bag of tricks and optimize bacterial metabolic engineering to develop an economically viable, truly green route for biofuel production,” said Roy Curtiss, director of the Biodesign Institute's Centers for Infectious Diseases and Vaccinology and Microbial Genetic Engineering as well as professor in the School of Life Sciences.

Cyanobacteria are like plants, dependent upon renewable ingredients including sunlight, carbon dioxide and water that, through genetic engineering, can be altered to favor biodiesel production. Cyanobacteria offer attractive advantages over the use of plants like corn or switchgrass, producing many times the energy yield with energy input from the sun and without the necessity of taking arable cropland out of production.

Colleague Xinyao Liu and Curtiss have spent the last few years modifying these microbes.  Their goal is to bypass costly processing steps (such as cell disruption, filtration) for optimal cyanobacterial biofuel production.

“We wanted to develop strains of cyanobacteria that basically can process themselves,” said Curtiss. “A couple of years ago, we developed a Green Recovery process that is triggered by removing carbon dioxide to control the synthesis of enzymes, called lipases, that degrade the cell membranes and release the microbes’ precious cargo of free fatty acids that can be converted to biofuels,”

However, when growth of cyanobacteria is scaled up to meet industrial needs, they become dense, and the self-shading that occurs in concentrated cultures, does not let in enough light to produce enough of the lipases to efficiently drive the process. Thus the original Green Recovery was light dependent and maximally efficient at sub-optimal culture densities.

Curtiss’ team looked again at nature to improve their Green Recovery method. The process uses enzymes found in nature called thermostable lipases synthesized by thermophilic organisms that grow at high temperatures such as in hot springs. These thermostable lipases break down fats and membrane lipids into the fatty acid biodiesel precursors, but only at high temperatures. The team’s new process, called thermorecovery, uses a heat-triggered, self-destruct system. By taking a culture and shifting to a high temperature, the lipases are called into action. This process occurs with concentrated cultures in the dark under conditions that would be very favorable for an industrial process. 

They tested a total of 7 different lipases from microbes that thrive in hot springs under very high temperatures, a scorching 60-70 C (158F). The research team swapped each lipase gene into a cyanobacteria strain that grows normally at 30 C (86 F) and tested the new strains.

They found the Fnl lipase from Feridobacterium nodosum, an extremophile found in the hot springs of New Zealand, released the most fatty acids. The highest yield occurred when the carbon dioxide was removed from the cells for one day (to turn on the genes making the lipases), then treated at 46C (114F) for two days (for maximum lipase activity).

The yield was 15 percent higher than the Green Recovery method, and because there were less reagents used, time (one day for thermorecovery vs. one week for Green Recovery) and space for the recovery.  Thermorecovery resulted in an estimated 80% cost savings.

Furthermore, in a continuous semi-batch production experiment, the team showed that daily harvested cultures released could release a high level of fatty acid and the productivity could last for at least 20 days. Finally, the water critical to growing the cultures could be recycled to maintain the growth of the original culture.

“Our latest results are encouraging and we are confident of making further improvements to achieve enhanced productivity in strains currently under construction and development,” said Curtiss. “In addition, optimizing growth conditions associated with scale-up will also improve productivity."

The results appear in the online version of the Journal of Biotechnology:

Joe Caspermeyer

Manager (natural sciences), Media Relations & Strategic Communications


ASU fetes Hao Yan as inaugural Glick Chair

September 27, 2012

In a celebration before a packed house at the Biodesign Institute, ASU professor Hao Yan was honored as the inaugural Milton D. Glick Distinguished Chair of Chemistry and Biochemistry.

The award is named for chemistry professor Milton “Milt” Glick who passed away last year. Glick came to ASU in the early 1990s and served for 15 years – first as senior vice president, and then as ASU’s chief academic officer as provost and executive vice president, before assuming the presidency of the University of Nevada Reno from 2006 until his death. Headshot of Hao Yan Download Full Image

“Milt was one of America’s great educators, and helped ASU become a great university through his 15 years of leadership, intellect and drive," said Crow. “Since Milt started out his career as a chemistry professor, we wanted to honor one of the very brightest chemistry faculty stars here at ASU, professor Hao Yan.”

Yan is a recognized leader in the fast-moving field known as structural DNA nanotechnology, or DNA origami, that self-assembles DNA into a broad range of technological applications important for human health and bio-electronic sensing devices. Yan’s inspiration to his lab, students and break-neck speed of developing new technologies may spark a ‘bottom up’ nanotechnology industry to developing new solutions in medicine, energy and electronics.

“I am very honored and humbled to be the recipient of this great honor by the Glick family and President Crow,” said Yan. "I’d also like to give a special thanks to Stuart Lindsay, the director of Biodesign’s Center for Single Molecule Biophysics, who was instrumental in originally recruiting me to ASU, with its vision of performing science in service to society and solving grand challenges. This is truly a memorable moment for me, my family and my lab.”

In addition to his research team’s scientific achievements that have braced the covers of leading research journals such as Science and Nature, Yan is just as dedicated in the classroom. As a professor in the Department of Chemistry and Biochemistry, in the College of Liberal Arts and Sciences, Yan has created an interactive environment in undergraduate and graduate courses that allows students to participate in class discussions, developed graduate courses that integrate research advances in cutting-edge interdisciplinary classes, and mentored and inspired students to be original thinkers in both research and the classroom.

Joining the celebration were well-wishers from across ASU and members of the Glick family, including widow, Peggy Glick. 

“I think Milt would be thrilled with this way of remembering him here,” said Glick. “He would be thrilled with associating him with the words ‘distinguished professor’. He would be thrilled that, with this professorship, there is one more of those ‘franchise players’ that he used to talk about at every department meeting. And he would happy to know it happened at this university, where he was the provost for so long, and where he really grow up as an academic administrator.”

A longtime friend of Glick’s on the ASU faculty, Regents' Professor and poet Alberto Rios, capped off the occasion with a special composition.  

Alberto Rios
The Chemist
            Who sees his work in all things is never lost.
Whose life has been iron and vapors in fire,
The elements themselves
Gathered in their thousand meetings
Tasked with making the things of the world,
Who has given and in that giving collected
An equal and like reward, a life served well
Serving yet, finished with nothing
But what is left behind, ahead
Undone and alive with still-to-do,
Humming with wanting-to-do,
Who has made a chemistry of days,
One day joined to a next, seven to five,
Five to five, a quarter to five, 365¾
That great molecule of time
All the alchemy of a single moment
Necessary, again and again, a year of days,
A day of hours, an hour full of work
And humor too, a hat worn on the heart.
This is the science of a man,
The science of composition, structure,
Properties, reactions of matter,
And of what matters. 
Joe Caspermeyer

Manager (natural sciences), Media Relations & Strategic Communications