Fueled by the Sun: Green Gold

Researchers across the college aim to harvest biofuels from plants and algae. Part 2 of the series, Fueled by the Sun.

This is Part II of a two part series. Read Fueled by the Sun: Mimicking Plants, an article about creating fuel from artificial photosynthesis.

In Malcolm Brown’s dream of a sustainable future, the sun rises every morning on oil-rich lands in West Texas that the university has owned since the early 20th century. Instead of oil derricks studding the land, however, what he sees are pools and pools of cyanobacteria known as bluegreen algae.

The blue-green algae have been grown by Brown so that their photosynthetic machinery takes the hot Texas sun, combines it with carbon dioxide, nutrients and briny water, and secretes sugar upon demand. That sugar, in turn, is fed to genetically engineered yeasts and bacteria that then secrete hydrocarbons that can be used as fuel.

As a byproduct, the cyanobacteria biomass can be converted to fertilizer or gasified for additional energy production on site.

The world is transformed. Cars and planes run on home-grown, endlessly renewable gasoline that takes as much carbon dioxide out of the air at the front end of the process as it releases at the end, when the gas burns.

And, to top it off, it’s the university that profits from all this blue-green gold.

“It’s so simple, it’s beautiful,” says Brown, a professor of biology and holder of the Johnson & Johnson Chair. “We use the land that has produced the oil in the past, and the infrastructure that’s already there, and even the resources that are still underground—briny water and carbon dioxide used for old oil field recovery—to produce a new energy source from the sun. And all of this could be accomplished in our great state of Texas.”

Brown is one of a cadre of scientists in the College of Natural Sciences whose goal isn’t to mimic plants and other photosynthesizers, but to enhance the organisms’ natural abilities to produce fuel.

The challenge involved in getting there with blue-green algae, says Brown, is not so much the science as it is the money. Brown believes he has the science in sight, but needs the funding to prove he can scale up. And in terms of money, says Brown, a lot less might be needed than most would think.

“If we could get our production of biomass to a certain level, then the economics are going to become self-evident,” he says. “We grew some cyanobacteria last summer in ponds at the Brackenridge Field Laboratory [BFL] that yielded the equivalent of 14.5 tons of sugar per acre per year. That was with all the clouds, and the temperature fluctuations, and not always knowing what we were doing. Is that enough to make it a commodity crop on a large scale? The answer is probably not, but if we could get it up to 50 tons per acre per year, then maybe we’re there. We’re doing that now in the lab. It’s more idealized in the lab, but at least it proves that it can be done.”

Fuels from Grass

Just down from Brown’s ponds of blue-green algae at BFL, rows of cultivated native switchgrass plants are taking root where they may once have grown wild.

Biologists Tom Juenger, Christine Hawkes and Tim Keitt are looking at how this potentially fuel-rich native plant will grow as a fuel crop under future climate conditions, working with a multi-million dollar grant from the National Science Foundation’s Plant Genome Research Program. Their challenge is a hotter, more arid future on the horizon.

“One thing to take into account when considering biofuel sources of energy,” says Juenger, “is that our estimates for productivity are based largely on yields from really good agricultural lands. The truth, however, is that if biofuel crops are going to be viable they will need to be productive on marginal land, with few inputs, and under more stressful environmental conditions. Many studies, to this point, have focused on which switchgrass cultivars are productive in which locations across the U.S., and yet the question we really need to be asking is which locations and cultivars will be productive in 20 or 40 years, based on predictions of climate change.”

Toward that end, the team has begun to embark on a variety of studies with USDA partners at the Lady Bird Johnson Wildflower Center, BFL and further afield.

Hawkes is subjecting switchgrass varieties to a range of future drought conditions in order to link the ecological and genetic responses of plants to drought and identify particularly promising switchgrass varieties for future biofuel development. Juenger will be developing genomic resources and tools for exploring physiological traits in switchgrass, including a switchgrass species native to Texas. He hopes to identify the genetic mechanisms of drought tolerance and adaptation in the species. And Keitt will use ecological models to predict the future yields of different switchgrass varieties and play out scenarios for how other crops and plant species would fare under climate change.

Algae to the Rescue

For biologist Jerry Brand, algae is the dream, but not just the blue-green kind. There are hundreds of thousands of different species of algae, native to nearly every aquatic ecosystem on the planet, growing and blooming in colors of red and green, brown and yellow, gold and a thousand shades in between. In Brand’s vision, it’s this diversity of algae that could change the landscape of how we think about our fuel economy.

All over the world—even in the oceans—algae could be grown simply, densely and efficiently, with the particular species varying with the climate, the local economic calculus and the resources available to refine or process it. One species might be suitable for a fairly straightforward gasification, in which the whole biomass is burnt and the resulting gas is captured as a fuel. Another species, with a high natural oil content, might be treated more delicately, with the oil extracted and purified as a source of fuel, while the remainder is sold as a nutrient or made into a pharmaceutical.

Brand, a professor of biology and the director of the university’s UTEX Culture Collection of Algae, believes that several broad challenges stand between us and such a future. Among them is the need to build up a scientific infrastructure that can bridge the chasm between the academy and industry.

Brand is working to transform UTEX, which is already one of the biggest and most diverse collections of algae in the world, into ground zero for algae collaboration and innovation.

“We already have some of the best algae scientists here at the university,” says Brand. “We also have one of the best collections of living algae, but our algae library and the facilities that house it weren’t designed with commercial development in mind. The dream is for The University of Texas at Austin to be the first and the best to do that.”

With such an infrastructure in place, says Brand, the university would be even better equipped than it is now to make a dent in the basic science left to be done before the cost of fuels from algae can be made competitive with fossil fuels. It will also be a louder voice to add to what ultimately has to be a global chorus demanding that we attack the problems of climate change and fossil fuel dependency from a host of different angles.

“Electricity-producing technologies such as wind, solar and nuclear power come to mind as alternatives to fossil sources of energy,” says Brand. “But the transportation infrastructure of the modern world and the strategic needs of the U.S. call for high-density sources of energy that can be transported long distances and stored in huge quantities over extended periods of time—which electricity cannot do. No airplane will fly between cities on electricity in the foreseeable future.

“Fossil fuels have served this need for a long time, but supplies are diminishing and the resulting carbon dioxide load is increasingly alarming. I believe that algae can provide an alternative that is sustainable, and with more research, affordable. My dream for the longer term, perhaps many decades away, is that an artificial photosynthesis which uses sunlight to convert carbon dioxide into fuel compounds on a massive scale without the need for a living organism will be developed.”