Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineering alternative fuel with cyanobacteria

10.01.2013
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, sholmes@sandia.gov, (505) 844-6362

Sue Holmes | EurekAlert!
Further information:
http://www.sandia.gov

More articles from Life Sciences:

nachricht Scientists unlock ability to generate new sensory hair cells
22.02.2017 | Brigham and Women's Hospital

nachricht New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>