[USA] La Jolla’s Synthetic Genomics and oil giant ExxonMobil said Monday that they have created an oil-rich strain of algae that represents a major research advance toward commercializing algae-based biofuels.
Researchers have doubled lipid content in a genetically engineered strain of Nannochloropsis gaditana, the companies said in a study published in the journal Nature Biotechnology. The level has been increased from about 20 percent in the natural form of this edible ocean algae to 40 to 55 percent in the engineered strain.
Moreover, this increase comes without significantly reducing the algae’s growth rate, the study said. And the oil-like lipids from may potentially be processed in existing refineries and used like diesel.
Key authors of the new report were Imad Ajjawi and Eric Moellering. Both are from Synthetic Genomics, co-founded by genomics pioneer J. Craig Venter. Go to j.mp/sgbiofuel for the study.
Much more work needs to be done before this strain can be taken out of the lab and commercially produced in the open, the authors said. The yield and growth need to be optimized for outdoor conditions, and environmental regulatory procedures need to be followed. Finally, the lower price of fossil fuels poses a financial barrier to adoption.
These concerns need to be balanced against the potential benefits of biofuel in providing renewable energy. This could be useful for energy security and could reduce damage if future global warming takes place.
“It’s a step change for us and a turning point in the program,” said Rob Brown, another author of the new study and head of the phototrophic team at Synthetic Genomics. “We want to get it out in the public domain and show people what we’ve been doing.”
ExxonMobil is taking a long-term view, Brown said.
The genetically engineered strain inhibits a suppressor of lipid production. The work was built on the observation that Nannochloropsis produces more lipids in a low-nitrogen environment.
Using various tools, the team identified certain genes that were inhibited in this low-nitrogen environment, then they set out to identify those that regulated lipid production. They found one that met all tests. Using this knowledge, they employed the popular CRISPR-Cas9 genome editing system to inhibit that gene.
The work produced three candidate lines. One of them not only produced more lipids, but also maintained a growth rate near that of the unmodified type. That line became the basis of the Nature Biotechnology study.
More lipids are produced because with less nitrogen, it’s not possible to make as much protein, Moellering said. Protein contains a lot of nitrogen. So the algae uses the photosynthetic energy to make lipids, which are made up of hydrogen and carbon. One of the purposes of the strain is to remove carbon dioxide from the atmosphere, believed to help inhibit global warming.
“The energy source is light, in this case from a light bank that we’ve engineered that mimics the intensity of the sun as the day progresses,” Moellering said.
ExxonMobil views biofuels research as a means of coming up with more options for the company and its customers around the world, Vijay Swarup, vice president of research and development, said at a Monday news conference on the study.
The goals to meet are immense, Swarup said, including building up the large-scale industrial capability to grow enough algae. But before any of that can be done, the science must indicate it’s feasible.
“The algae biofuels program was always based on that belief — that you can have something that is fast-producing, doesn’t compete with food or fresh water, and can grow in multiple climates, multiple geographies,” Swarup said.
The research program has had its times of frustration, he said, but the doubling of biofuel production in algae indicates the program is on the right track.
“This is one big step toward this,” Swarup said. “We still think we’re several decades away. But we’re moving one step at a time.”
The ExxonMobil/Synthetic Genomics alliance began in 2009 when the companies announced a major partnership to develop algae-based biofuels.
Since then, fossil fuels have staged a major comeback. Contrary to “peak oil” predictions around the turn of the century, prices have plummeted due to improvements in fracking technology. The same is true for natural gas. Moreover, a huge untapped fossil fuel source, methane hydrates, is being explored.
And the scientific path also proved unexpectedly difficult, Brown said. The original goal was to find natural algae that could be isolated with the desired characteristics.
“It was rather ambitiously started in the early days of 2009, when we thought we were going to get wild-type species that would be deployed at industrial scale in these big open ponds,” Brown said.
“We hit a few roadblocks and reset the program, based on not being able to find a wild-type algal species,” he said. “Craig (Venter) has mentioned the way to remedy this was to use the bells and whistles in Synthetic Genomics’ wheelhouse to engineer (improvements in) the best-producers that Mother Nature can provide you.”
Brow said the Nature Biotechnology study shows the results of this approach, which was adopted in 2012. By delving into the molecular biology, the team was able to identify an important genetic regulatory mechanism and engineer it to make more biofuel.
While this work is all done in the lab, it will eventually translate into algae ready for testing in an open-pond environment, he said, a step toward scaling up to industrial production.
“We have a very patient partner with ExxonMobil,” Brown said. “They want to get it right by making a commitment to solving the fundamental biology first. Other companies that have attempted this and failed was because they didn’t have this long-term vision.”
And outdoors production of a genetically modified organism requires approval from state and federal regulators, he said.
“So we are a ways out,” Brown said. “This is still a research program at (Synthetic Genomics).”
The outdoor use of genetically modified algae recently got a boost in an unrelated study from UC San Diego and the San Diego-based company Sapphire Egnery.
The study found that genetically engineered algae had no more impact on biodiversity than introduced natural strains, and neither outcompeted strains native to the area.
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