Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 


Engineering alternative fuel with cyanobacteria

Sandia National Laboratories Truman Fellow Anne Ruffing has engineered two strains of cyanobacteria to produce free fatty acids, a precursor to liquid fuels, but she has also found that the process cuts the bacteria’s production potential.
Micro-algal fuels might be one way to reduce the nation’s dependence on foreign energy. Such fuels would be renewable since they are powered by sunlight. They also could reduce carbon dioxide emissions since they use photosynthesis, and they could create jobs in a new industry. President Barack Obama, speaking in February at the University of Miami, advocated for investments in algae fuel development, saying they could replace up to 17 percent of the oil the United States now imports for transportation.

“Even if algae are not the end-term solution, I think they can contribute to getting us there,” Ruffing said. “Regardless of however you look at fossil fuels, they’re eventually going to run out. We have to start looking to the future now and doing research that we’ll need when the time comes.”

She has been studying the direct conversion of carbon dioxide into biofuels by photosynthetic organisms under a three-year Truman Fellowship that ends in January. She presented her project at a poster session in August and published her work on one strain, “Physiological Effects of Free Fatty Acid Production in Genetically Engineered Synechococcus elongatus PCC 7942,” as the cover article in the September 2012 issue of Biotechnology and Bioengineering.

Ruffing considers her studies as proof-of-concept work that demonstrates engineering cyanobacteria for free fatty acid (FFA) production and excretion. She wants to identify the best hydrocarbon targets for fuel production and the best model strain for genetic engineering, as well as gene targets to improve FFA production.

She is using cyanobacteria — blue-green algae — because they are easier to genetically manipulate than eukaryotic algae, the natural “oil”-producing photosynthetic microorganisms more commonly used for algal biofuels, and because cyanobacteria can be engineered to create a variety of target fuels. Genetically engineered cyanobacteria excrete FFA and allow fuel to be collected without harvesting the cyanobacteria. This lowers the requirement for nitrogen and phosphate and reduces costs.

But current yields from engineered strains are too low for large-scale production.
Truman Fellow Anne Ruffing looks at a flask of cyanobacteria with precipitated fatty acid floating on top. She has engineered two strains of cyanobacteria to produce free fatty acids, a precursor to fuels, as she studies the direct conversion of carbon dioxide into biofuels by photosynthetic organisms. (Photo by Randy Montoya) Click on the thumbnail for a high-resolution image.

Ruffing favors cyanobacteria because fuel from engineered cyanobacteria is excreted outside the cell, in contrast to eukaryotic algae, in which fuel production occurs inside the cell.

In general, this is how the process works: Eukaryotic algae grow in a pond to the density needed, then producers must get rid of the water, collect the cells and break them open to get the fuel precursor inside. This precursor is isolated and purified, then chemically converted into biodiesel. Cyanobacteria excrete the fuel precursor outside the cell, so a separation process can remove the product without killing the cells. That eliminates the need to grow a new batch of algae each time, saving on nitrogen and phosphate.

While other research efforts have focused on metabolic engineering strategies to boost production, Ruffing wants to identify what physiological effects limit cell growth and FFA synthesis.

“You can’t really hope to continue to engineer it to produce more of the fatty acids until you address these unforeseen effects,” she said. “As much as you want to do the applied side of things, creating the strain, you can’t get away from the fundamental biology that’s necessary in order to do that.”

Much of our fundamental understanding of photosynthesis comes from cyanobacteria, but it’s only been in the past decade or so, with advances in gene manipulation and recombinant DNA technology, that they’ve been considered for fuel production, Ruffing said.

The strains she engineered for FFA production show reduced photosynthetic yields, degradation of chlorophyll-a and changes in light-harvesting pigments, Ruffing said. She saw some cell death and lower growth rates overall, and suspects the toxicity of unsaturated FFA and changes in membrane composition are responsible.

Now she’s looking at what genes are changing when cyanobacteria produce fatty acids. She’s creating mutants by knocking out certain genes or introducing or overexpressing genes to see how that affects the cell and fatty acid production.

“So I’m engineering the cell, then I’m trying to learn from the cell how to work with the cell to produce the fuel instead of trying to force it to produce something it doesn’t want to produce,” she said.

She’s producing FFA from Synechococcus elongatus PCC 7942 and Synechococcus sp. PCC 7002, chosen as so-called model organisms that have been studied for several decades and for which tools exist to manipulate their genes. She also is working with the two strains and a third, Synechocystis sp. PCC 6803, for biofuel toxicity screening.

Ruffing hopes to continue working on strain development after the fellowship ends.

“It is possible that there’s a natural strain out there that could be a better option, so this is still pretty early research,” she said. “There’s a lot of exploration to do.”
Sandia National Laboratories is a multiprogram laboratory operated and managed by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia news media contact: Sue Holmes,, (505) 844-6362

Sue Holmes | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Two decades of training students and experts in tracking infectious disease
27.11.2015 | Hochschule für Angewandte Wissenschaften Hamburg

nachricht Increased carbon dioxide enhances plankton growth, opposite of what was expected
27.11.2015 | Bigelow Laboratory for Ocean Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tübinger Forscher entdecken neue Zelltypen im Gehirn

Untersuchung im Neocortex von Mäusen - Zusammenarbeit mit Wissenschaftlern aus Houston

Wissenschaftler aus Tübingen und Houston haben zahlreiche neue Zelltypen im Gehirn identifiziert. Im Neocortex von erwachsenen Mäusen führten sie erstmals eine...

Im Focus: Klimawandel: Forscher weisen dramatische Veränderung in den 1980er Jahren nach

Ende der 1980er Jahre erlebte die Erde eine dramatische Klimaveränderung. Sie umfasste die Tiefen der Ozeane ebenso wie die obere Atmosphäre und reichte vom Nord- bis zum Südpol. Ausgelöst durch den Ausbruch des Vulkans El Chichón in Mexico 1982 und verstärkt durch menschliches Handeln folgte daraus die größte Temperaturverschiebung der letzten 1.000 Jahre. Erstmals nachgewiesen hat dies ein internationales Forscherteam um Prof. Philip C. Reid von der Plymouth University und der Sir Alister Hardy Foundation for Ocean Science (UK). Die Ergebnisse wurden kürzlich in der Fachzeitschrift „Global Change Biology“ veröffentlicht.

Abrupte Klimaveränderungen haben oft dramatische Folgen für unseren Planeten. Dennoch sind sie in ihrer Art, ihrem Ausmaß und in ihrer Wirkungsweise meist nur...

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaik – vom Labor an die Fassade

Fraunhofer ISE demonstriert neue Zell- und Modultechnologien an der Außenfassade eines Laborgebäudes

Das Fraunhofer-Institut für Solare Energiesysteme ISE hat die Außenfassade eines seiner Laborgebäude mit 70 Photovoltaik-Modulen ausgerüstet. Die Module...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Alle Focus-News des Innovations-reports >>>



im innovations-report
in Kooperation mit academics

Bürger treffen Experten: Gespräch zu Chancen und Risiken der Nanotechnologie am 30.11.2015

27.11.2015 | Veranstaltungen

Arbeit in Sozialen Dienstleistungen - Welche Zukunft hat die Branche?

27.11.2015 | Veranstaltungen

Konzepte nutzergerechter Fahrerarbeitsplatzgestaltung

26.11.2015 | Veranstaltungen

Weitere VideoLinks >>>
Aktuelle Beiträge

Künstliche Herzklappe nach dem Vorbild der Natur

27.11.2015 | Förderungen Preise

Siemens liefert 126 Megawatt Onshore-Windleistung nach Schottland

27.11.2015 | Unternehmensmeldung

Hauptkläranlage Wien wird mit Siemens zum Ökokraftwerk

27.11.2015 | Energie und Elektrotechnik