Saltwater algae just fine for biobased fuels, products: new research

| November 27, 2012

Newly published report removes key sustainability doubts.

“Ocean water is simply not a limited resource on this planet,” says research team.

You may have found yourself recently disheartened by a National Academy of Sciences report that algal biofuels production might be be constrained by fresh water availability. The NAS report said that no published research study had demonstrated the feasibility of using engineered marine species of algae.

Well, good news. Less than a month after the arrival of the NAS report, comes a paper in the scientific journal Algal Research that demonstrates it. The feasibility, that is.

Master of the Marsh

“The algal community has worked on fresh water species of algae for 40 years,” said Stephen Mayfield, a professor of biology at UC San Diego, who headed the research project and directs the San Diego Center for Algae Biotechnology.

“We know how to grow them, manipulate them genetically, express recombinant proteins—all of the things required to make biofuels viable.  It was always assumed that we could do the same thing in marine species, but there was always some debate in the community as to whether that could really be done. “But now we’ve done it,” said Mayfield. “What our research shows is that we can achieve in marine species exactly what we’ve already done in fresh water species.”

“What this means is that you can use ocean water to grow the algae that will be used to produce biofuels. And once you can use ocean water, you are no longer limited by the constraints associated with fresh water. Ocean water is simply not a limited resource on this planet.”

The project

The UC San Diego biologists focused their study on a marine species of alga, Dunaliella tertiolecta, which had been earlier targeted by scientists for potential biofuels production because of its high oil content and ability to grow rapidly under a wide range of salinity and acidic conditions. To demonstrate that it could be used in commercial biofuel production, they introduced five genes into the alga that produced five different kinds of enzymes that could be used in an industrial setting to not only convert biomass to fuel, but also increase nutrient availability in animal feed. Some of these enzymes, for example, came from a fungus that degrades plant material into simple sugars.

The UC San Diego biologists collaborated on the research with scientists from Sapphire Energy, Inc., an algae company that is operating a saltwater algae farm in Columbus, New Mexico that is expected to be producing 100 barrels per day of Green Crude oil in 2013.

Expanding the field

The ability to genetically transform marine algae into a biofuel crop is important because it expands the kinds of environments in which algae can be conceivably grown for biofuels.

Corn, for example, which is used to produce ethanol biofuel, requires prime farmland and lots of fresh water.

But the UC San Diego study suggests that algal biofuels can be produced in the ocean or in the brackish water of tidelands or even on agricultural land on which crops can no longer be grown because of high salt content in the soil.

How much production, how much land

According to Mayfield, there are about 10 million acres of land across the United States where crops can no longer be grown that could be used to produce algae for biofuels.

And, according to a Pacific Northwest National Laboratory’s (PNNL) report, algal fuels grown in saline water from existing aquifers and recycling nutrients would be able to provide up to twice the goal for advanced biofuels set under the Energy Independence and Security Act (roughly 40 billion gallons or 20 percent of annual transportation fuel demand).

Reaction from the Algal Biomass Organization

“The results of Dr. Mayfield’s research should remove concerns about the exclusive use of fresh water to scale commercial production of algae for fuel and other co-products,” said Mary Rosenthal, ABO’s executive director. “Although leading algae production companies are already leveraging saline aquifers and ocean water, this publicly-available paper will update the current body of research on the topic of sustainability of algae production.

The bottom line

There are a couple of “remains to be seen” issues before the bubbly can be broken out in terms of marine algae biofuels.

One – can it be grown industrially, at scales and costs that are significant for fuels? Sapphire is working on that.

Two, how much of the 10 million acre footprint of land can be tapped for biofuels at scale – where there is brackish or saline water, but not sufficient freshwater for traditional agriculture? There is more than industrial process, and algae growth and oil profile characteristics that need to be fully divined. To use one incredibly mundane example, it is enormously helpful is the land is not completely flat, but exists on a slight grade that encourages water to move through gravity, instead of costly paddle-wheels.

The good news? Surely this expands the footprint – or, rather, confirms that a sustainable land-base will be available in terms of water usage. With productivities in the 3000-7000 gallon per acre level, every acre is highly significant in the chase for renewable fuels.

Tags: , ,

Category: The A-List

Comments (0)

Trackback URL | Comments RSS Feed

There are no comments yet. Why not be the first to speak your mind.

Comments are closed.