World not yet ready for super algae

Algae has received attention for its promise in producing biocrude oils. But what if it could also be modified to produce large quantities of hydrogen at the same time?

Could that change the economics of algae?

Ben Hankamer, director of the Solar Biofuels Consortium, is leading an international team experimenting with a new genetically modified algal strain that appears able to make significant amounts of 90 percent pure hydrogen, while also producing oil for biofuel or other purposes. However, they’re genetically modified organisms (GMOs), and currently restricted to the lab.

While algae emit a small amount of hydrogen naturally during photosynthesis, the new strain has been specifically modified to do so at large scale.

“We’ve developed mutants that produce hydrogen,” Hankamer, also an associate professor at the University of Queensland, Australia, told the Cleantech Group.

Hankamer first published about the breakthrough in 2005, and patented the engineered algal strain this year with colleague Olaf Kruse of the Bielefeld University, Germany.

Hankamer, who relocated to Australia from his native London, said his work builds on that of Tasios Melis of the University of California at Berkeley. Melis first restricted sulfur from the diet of the common C. reinhardtii algae, and induced the organisms into emitting hydrogen instead of water when he was a colleague of Michael Seibert and Maria Ghirardi at the U.S. National Renewable Energy Laboratory in Colorado.

Hankamer and Kruse’s mutant strain of C. reinhardtii, named Stm6, produces more hydrogen than Melis’. And while it’s only one to 1.5 percent efficient today in its hydrogen production, vast improvement is possible, he said.

“Theoretically you can get to 12 percent conversion efficiency from light to hydrogen [using the algae]. You can get to only about eight using oils, according to [U.C. Berkeley’s] Melis. The reason’s quite simple: if you look at the reaction schemes, the longer they are, the more energy loss there is. It’s like having a very long work process and losing energy at every stage.”

“To my knowledge, we’ve patented the highest hydrogen producing cell lines there are,” he said, noting that the consortium has not yet been able to enter into field trials, which would require specific approval to use its GMOs in the wild.

While touted for its potential as a clean fuel, hydrogen has traditionally been produced from fossil fuel sources. CO2 is generated in its production, which has also required large amounts of electrical power and water.

The new hydrogen-producing cell lines produce the same sugars and starches that form the oils coveted for algae biofuel applications, Hankamer said, which in theory could give algae farms two revenue streams: hydrogen and algal biocrude, making them therefore more cost effective.

Hankamer’s Solar Biofuels Consortium is funded by 10 industry partners. Seven teams are spread over Australia, Germany and the UK, with some 70 people total, are working on algae bioengineering, bioreactor design, use of algae for CCS and other applications.

In a related development, the consortium claims it has succeeded in improving the light capture of C. reinhardtii by genetically modifying it to remove its antenna proteins. This modification is said to result in the same yield of biomass in half the time, by allowing more light to reach more algae in the same volume of space. It also changes the color of the algae from dark green to light green. The group published its finding earlier this year.

The Solar Biofuels Consortium says it has developed economic models that it says show very compelling IRR for algae projects that produce oil, biomass and another high value product, with actual specifics depending on a number of variables.

Historically, algae project profitability has been impeded by the high capital cost of photobioreactors and net energy balance concerns when raising algae in open ponds. New innovations in strains and bioreactors have the potential to change that, according to Hankamer.

The challenges facing widespread use of the consortium’s work are not just technical, but political as well—especially when genetically modified organisms are concerned.

“There will probably be different algae for different countries because of legislation. Can you imagine me trying to import an Australian strain into California? Or for that matter trying to import other strains from outside into Australia with its quarantine regulations,” Hankamer said.

As promising as the consortium’s new cell lines are, its technology has only been proven in the lab. Hankamer and colleagues have raised funding for limited trials, but could use additional capital, he said, and are looking into whether U.S. partners make sense.

While fringe science for 60 years, investors have recently been putting increasingly large amounts of money into algae research and commercialization, including large oil companies (see ExxonMobil devotes $600M to algal biofuel project with Synthetic Genomics and Shell to grow algae for biofuel).

Hankamer visited the United States this month courtesy of the Eisenhower Fellowships, a grant program that engages emerging leaders around the world to for professional development and broadening their contacts.

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