That debate came to a head last month when a National Academy of Sciences committee examining the future potential of algal biofuels for the U.S. Department of Energy published a report pointing out that the production of algal biofuels might be limited by fresh water because no published research study had demonstrated the feasibility of using engineered marine species of algae.
"But now we've done it," said Mayfield. "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 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 scientists said in their paper that "we hope to eventually determine whether whole algae, post-oil extraction, may be used as a feed additive to improve animal feeds. Animal feed is a relatively high volume market that may be able to benefit from algae-produced proteins as a feed additive."
|Contact: Kim McDonald|
University of California - San Diego