Syracuse University
Scientists have long known of the potential of microalgae to aid
in the production of biofuels and other valuable chemicals.
However, the
difficulty and significant cost of growing microalgae have in some ways stalled
further development of this promising technology.
Bendy Estime, a biomedical
and chemical engineering Ph.D. candidate, has devoted his research to this
area, and developed a new technology for energy efficient cultivation and
harvesting of microalgae.
He and his research
advisors, Distinguished Professor Radhakrishna Sureshkumar, chair of the
Department of Biomedical and Chemical Engineering, and Professor Dacheng Ren,
have secured a provisional patent for the technology.
"My goal was to improve the growth of microalgae,"
says Estime, who first studied biofuels as an engineering student in his native
Haiti.
"The study is an attempt to address three 'bottlenecks' in
microalgae cultivation," says Sureshkumar.
"When you grow algae in
suspension, they tend to stick to the walls of a container, making the
container opaque. This makes it more difficult for required light to get
through to the algae. The second issue is that there has to be consistent
stirring of the container to ensure that light does reach all layers of the
algae. A third issue is the difficulty of separating algae from the broth,
which requires time and energy, and is therefore costly."
Estime developed a new medium to culture and harvest microalgae.
The medium, Tris-Acetate-Phosphate-Pluronic or TAPP, can transition from
solution to a gel through relatively small variations in temperature.
Microalgae are seeded in the medium at 15 degrees celsius. When the temperature
is increased by seven degrees, the medium becomes gelatinous. In this new
medium, microalgae grow in clusters that are up to 10 times larger than those
grown in the traditional medium.
Once they are grown, the temperature is
decreased, and the medium is returned to a solution. The algae is separated out
through gravity, and can then be harvested.
The medium prevents algae from growing on the sides of a
container, letting light penetrate to each level of algae. This eliminates the
need for constant stirring. When the medium is converted back to a solution,
algae can be more easily separated out and removed from the container.
"The industrial applications of this system are
appealing," Estime says. "This system would harvest microalgae 10
times faster than traditional systems and in an energy- efficient
fashion."
"This study presents a novel method to harvest algae and
other cells with low cost, which has potential applications in multiple
fields," says Ren, professor of biomedical and chemical engineering.
"It makes it more realistic for researchers to pursue microalgae as a
solution."
