Exploring Algae as Fuel
SAN DIEGO — In a laboratory where almost all the test tubes look green, the tools of modern biotechnology are being applied to lowly pond scum.
Foreign genes are being spliced into algae and native genes are being tweaked.
Different strains of algae are pitted against one another in survival-of-the-fittest contests in an effort to accelerate the evolution of fast-growing, hardy strains.
The goal is nothing less than to create superalgae, highly efficient at converting sunlight and carbon dioxide into lipids and oils that can be sent to a refinery and made into diesel or jet fuel.
“We’ve probably engineered over 4,000 strains,” said Mike Mendez, a co-founder and vice president for technology at Sapphire Energy, the owner of the laboratory. “My whole goal here at Sapphire is to domesticate algae, to make it a crop.”
Dozens of companies, as well as many academic laboratories, are pursuing the same goal — to produce algae as a source of, literally, green energy. And many of them are using genetic engineering or other biological techniques, like chemically induced mutations, to improve how algae functions.
“There are probably well over 100 academic efforts to use genetic engineering to optimize biofuel production from algae,” said Matthew C. Posewitz, an assistant professor of chemistry at the Colorado School of Mines, who has written a review of the field. “There’s just intense interest globally.”
Algae are attracting attention because the strains can potentially produce 10 or more times more fuel per acre than the corn used to make ethanol or the soybeans used to make biodiesel. Moreover, algae might be grown on arid land and brackish water, so that fuel production would not compete with food production. And algae are voracious consumers of carbon dioxide, potentially helping to keep some of this greenhouse gas from contributing to global warming.
But efforts to genetically engineer algae, which usually means to splice in genes from other organisms, worry some experts because algae play a vital role in the environment. The single-celled photosynthetic organisms produce much of the oxygen on earth and are the base of the marine food chain.
“We are not saying don’t do this,” said Gerald H. Groenewold, director of the University of North Dakota’s Energy and Environmental Research Center, who is trying to organize a study of the risks. “We say do this with the knowledge of the implications and how to safeguard what you are doing.”
At a meeting this month of President Obama’s new bioethics commission, Allison A. Snow, an ecologist at Ohio State University, testified that a “worst-case hypothetical scenario” would be that algae engineered to be extremely hardy might escape into the environment, displace other species and cause algal overgrowths that deprive waters of oxygen, killing fish.
A week earlier, at an industry-sponsored bioenergy conference, David Haberman, an engineer who has worked on an algae project, gave a talk warning of risks. Many scientists, particularly those in the algae business, say the fears are overblown. Just as food crops cannot thrive without a farmer to nourish them and fend off pests, algae modified to be energy crops would be uncompetitive against wild algae if they were to escape, and even inside their own ponds.
“Everything we do to engineer an organism makes it weaker,” said Stephen Mayfield, a professor of biology at the University of California, San Diego, and a co-founder of Sapphire. “This idea that we can make Frankenfood or Frankenalgae is just absurd.”
Dr. Mayfield and other scientists say there have been no known environmental problems in the 35 years that scientists have been genetically engineering bacteria, although some organisms have undoubtedly escaped from laboratories.
Even Margaret Mellon of the Union of Concerned Scientists, who has been critical of biotech crops, said that if genetically engineered algae were to escape, “I would not lose sleep over it at all.”
Still, some algae researchers worry they will be engulfed by the same backlash aimed at biotech foods and say care must be exercised. “About 40 percent of the oxygen that you and I are breathing right now comes from the algae in the oceans,” the genetic scientist J. Craig Venter said at a Congressional hearing in May. “We don’t want to mess up that process.”
Dr. Venter’s company, Synthetic Genomics, is getting $300 million from Exxon Mobil to create fuel-producing algae, in part by using synthetic genes. When the two companies cut the ribbon on a new greenhouse here earlier this month, Dr. Venter assured local dignitaries in attendance that no algae would escape. “Nothing will go into the drains, Mr. Mayor,” Dr. Venter said, only half-jokingly. “San Diego is safe.”
In the long run, Dr. Venter said, the algae should be given “suicide genes” that would kill them if they escaped the lab or fuel production facility. Some companies are sticking with searching for and breeding natural strains. “Re-engineering algae seems driven more by patent law and investor desire for protection than any real requirement,” said Stan Barnes, chief executive of Bioalgene, which is one of those companies. But Dr. Venter and Mr. Mendez argue that there are huge obstacles to making algae competitive as an energy source and that every tool will be needed to optimize the strains.
Sapphire Energy seems one of the best-positioned companies to do that. The company, which is three years old, has raised $100 million from prominent investors, including Bill Gates. Sapphire is also getting $100 million in federal financing to build a demonstration project containing 300 acres of open ponds in the New Mexico desert.
The company has inserted a gene into algae that allows the organisms to make a hydrocarbon they would not naturally produce, one that would help make fuel. “You don’t want to take what algae gives you,” said Mr. Mendez, who previously worked for medical biotechnology companies. “You want to make the best product.”
The company is also developing algae that can thrive in extremely salty and exceedingly alkaline water.
It has even developed what might be called Roundup Ready algae. Like the widely grown Roundup Ready soybeans, these algae are resistant to the herbicide Roundup. That would allow the herbicide to be sprayed on a pond to kill invading wild algae while leaving the fuel-producing strain unhurt.
Not all these traits are being developed by genetic engineering, because in many cases scientists do not know what genes to use. Instead, the company screens thousands of strains each day, looking for organisms with the right properties. Those desirable traits can be further enhanced by breeding or accelerated evolution.
In one room at Sapphire’s lab, parallel tubes contain algae with identical traits growing under identical conditions. But each strain is slightly different, and only the fastest growing one — determined by which tube turns the darkest green — will be chosen for further development.
“If you can’t outcompete your wild cousin, it doesn’t make it out of this room,” said Mr. Mendez. Algae can reproduce rapidly, doubling in as little as a few hours. And they can be carried long distances by the wind. “They have the potential to blow all over the world,” said Richard Sayre of the Donald Danforth Plant Science Center in St. Louis.
Dr. Sayre, who is also chief technology officer of Phycal, an algae company, is using genetic engineering to develop algae that capture less light. Right now, he explained, algae capture more light than they need and waste a lot of it as heat. If each organism captured less, then a given amount of light could be shared by more organisms, increasing biomass production.
Instead of using open ponds, some companies are using bioreactors, which typically contain the algae in tubes. Some experts say, however, that these would not totally prevent escapes. “The idea that you can contain these things and have a large-scale system is not credible,” said John R. Benemann, an industry consultant in Walnut Creek, Calif. He said, however, that he saw absolutely no risk from genetically engineered algae.
Sapphire says it is not growing any genetically engineered algae in open ponds yet. When it is ready, it says, it will comply with all regulations.
Genetically engineered algae, whether in open ponds or enclosed bioreactors, are likely to be regulated by the Environmental Protection Agency, which now regulates genetically engineered microbes under the Toxic Substances Control Act.
Still, there has been at least one case in which genetically modified algae seem to have fallen between the regulatory cracks. When Mera Pharmaceuticals, which is based in Hawaii, wanted to test the feasibility of producing human pharmaceuticals in genetically engineered algae in 2005, none of the three federal agencies that regulate the various areas of biotechnology — E.P.A., the Food and Drug Administration and the Agriculture Department — claimed jurisdiction.
Steven G. Chalk, acting deputy assistant secretary for renewable energy at the Energy Department, said any federally financed project, like Sapphire’s New Mexico demonstration, would have to undergo an environmental assessment. But risks would be assessed case by case, he said, not for all conceivable genetically modified algae.
Source: New York Times
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