Kathryn Coyne, assistant professor of marine biosciences, is studying algae as a source of biofuel and pollution control. Photo: University of Delaware
The tiny, plant-like Heterosigma akashiwo is too small to
see with the naked eye, but the microscopic algae may pack a big environmental
of Delaware researchers
are studying whether the species can neutralize harmful smokestack emissions—and
also serve as a source of eco-friendly biofuel.
The project is an outgrowth of biochemist Kathryn Coyne’s study into the
ecology of H. akashiwo, which thrives in Delaware and worldwide. Coyne and her
postdoctoral fellow, Jennifer Stewart, found that the algae contain a special
enzyme with the unusual ability to detoxify nitric oxide, one of multiple
contaminants released through industrial chimneys as flue gas.
Based on the discovery of that enzyme, Coyne and Stewart decided
to explore the possibility of recruiting the algae for pollution control. They
knew that other scientists were trying to use different types of algae to
reduce emissions of another flue gas component, carbon dioxide, since algae
need carbon dioxide to grow.
“The problem with those attempts was that the nitric oxide also
present in flue gas usually killed the algae,” said Coyne, assistant professor
of marine biosciences. “It’s very harmful.”
That’s where H. akashiwo’s special enzyme may come in
handy. The protein may enable the algae to convert harmful nitric oxide into
innocuous nitrate, while the algae are also metabolizing carbon dioxide.
An image of Heterosigma akashiwo, with the nucleus colored green and the chloroplasts blue. Image: University of Delaware
In addition to having pollution-fighting potential, H.
akashiwo is a proven source of biofuel. Rising petroleum prices and finite
quantities of fossil fuels are prompting demand for renewable energy sources,
and algae-derived biofuel is already powering some trains, jets and other
Adding nitrogen is an important but costly step in the process
of making biofuel. H. akashiwo’s ability to use nitric oxide from flue
gas essentially eliminates that step.
Coyne’s project is still in the early stages, having only
recently received funding from Delaware Sea Grant. Before investigating commercial
applications, Coyne will need to examine the long-term effects of flue gas on
the algae’s physiology. She will also evaluate how well H. akashiwo uses
nitric oxide as a nitrogen source and how light intensities affect its
production of the lipids and fatty acids used to make biofuel.
Yet the potential upsides could be great. Existing methods of
cleaning factory gas before it is released into the air are labor-intensive and
costly, so algae pose a natural and potentially cheaper alternative. They also
contain a high proportion of the fats needed to make biofuel.
“Algal biofuels are great values,” Coyne said. “Compared to
crops like corn and soybeans, the same mass of algae can produce greater
quantities of biofuel.”