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UM studies algae for nextgen biofuels

August 1, 2013, Ann Arbour, MI - A team of University of Michigan researchers has been awarded a $2 million US federal grant to identify and test naturally diverse groups of green algae that can produce next-generation biofuels.


July 31, 2013
By Scott Jamieson


Topics

National Science Foundation funding for the project begins Sept. 1
and will continue for four years. The effort will involve growing
various combinations of lake algae in 180 aquariums at a new
one-of-a-kind U-M laboratory, then field-testing the most promising
candidates inside 80 fiberglass cattle tanks at the university's E.S.
George Reserve, a 1,300-acre biological research station near Pinckney,
Mich.

The main goal is to test the idea that certain naturally diverse
groups of algae have complementary traits that enhance the efficiency
and stability of biofuel yield beyond what any single species can do
alone. The project involves an unusual collaboration among ecologists,
evolutionary biologists and engineers from four labs that will include
about 20 researchers and students.

"People have suggested that species diversity might increase the
efficiency of algal biofuel systems, but nobody has set up the
experiments to test it directly. These will be the first experiments to
systematically manipulate the number and types of species in the system
to determine how to maximize the yield and stability of algal biofuel,"
said ecologist and team leader Bradley Cardinale, an associate professor
at the U-M School of Natural Resources and Environment.

Researchers have been trying to make affordable transportation
fuels, such as biodiesel and jet fuel, from algae for several decades.
Most of the work has focused on finding single algal strains that are
highly productive, as well as identifying the ideal mix of nutrients and
environmental conditions. Genetically engineered "super-species" have
even been created in an effort to boost yields so that algae-based
biofuels can compete with fossil fuels.

But that dream has not been realized, largely due to multiple
problems that arise when you move a single-species, or monoculture,
algal system from the laboratory to a pond. In the great outdoors,
erratic weather, the invasion of unwanted algae species, and the
presence of voracious algae-eating microorganisms can wipe out the
"crop."

In addition, growing a single species of algae in a pond requires
huge amounts of nitrogen and phosphorus fertilizer, much of which ends
up as pollution after the crop is harvested. Add in the pesticides and
herbicides needed to control intruders and you have a costly system with
significant environmental impacts.

The U-M-led "biodiversity and biofuels" project aims to increase the
productivity and stability of algae-based biofuel systems while
reducing environmental impacts by recycling wastes and cutting the need
for biocides. The end result should be a more sustainable system that is
cheaper to operate.

"Rather than engineering a super-species of algae and fighting with
nature to maintain it as a pure monoculture through the use of
pesticides and herbicides, we propose to cooperate with nature by
identifying algal communities that naturally exhibit high biofuel
potential and the desired stability through time," said U-M chemical
engineer Phillip Savage, one of three project co-leaders. The other two
are U-M chemical engineer Nina Lin and evolutionary biologist Todd
Oakley of the University of California, Santa Barbara.

In his laboratory in the basement of U-M's Dana Building, Cardinale
has established cultures of 55 of the most common species of green algae
found in North American lakes.

The focus is on multiple species that naturally co-occur because
numerous studies have shown that diverse communities of plants
(including green algae) exploit resources more fully and collectively
produce more plant tissue than any single species alone. Diverse
communities are also more resistant to pests and invaders, can better
withstand environmental fluctuations and exhibit more stable yields over
time.

Starting around mid-September, Cardinale's lab will begin growing
various combinations of eight of the 55 algae species inside 2.4-gallon
plastic aquariums called continuous-flow chemostats. The amount of
nitrogen, phosphorus, light and carbon dioxide in each tank, as well as
the water temperature, will be tightly controlled.

The newly installed chemostats are meant to mimic lakes, and they
complement 150 mini-streams, called flumes, installed in the Dana
basement two years ago.

Taken together, the 330 chemostats and flumes constitute a
state-of-the-art laboratory that is unmatched by any facility in the
world, Cardinale said.

"No lab like this exists anywhere else. There's nothing else that even comes close to it," he said.

Using the chemostats, researchers will make multiple measurements of
the various algae combinations to assess their efficiency and yield.
Stability of the various combinations will be tested by measuring their
response to changes in water temperature and the introduction of
undesirable algae species.

The highest-scoring algae combinations from the first phase of the
project will move on to the next round, the 260-gallon cattle tanks at
the E.S. George Reserve, a set-up that mimics real-world, open-pond
algal-growth systems known as photosynthetic biorefineries.

U-M chemical engineer Savage's lab will use a technique called
hydrothermal liquefaction to measure the quantity and quality of the
combustible oils, or biocrude, produced by the various algae
combinations—from both the laboratory and field experiments. His team
also will compare the ability of single and multispecies systems to
reuse and recycle wastes for additional growth.

Lin is a U-M chemical engineer who employs microfluidics and
high-throughput screening technologies to "bio-prospect" for
microorganisms associated with biochemical or biomedical applications.
For the algae project, she is modifying various laboratory techniques so
the team can expand the search for multispecies assemblages that
exhibit high yields and efficient waste recycling.

By reconfiguring a device her lab originally developed for use with
bacteria, Lin should be able to screen more than a million algal species
combinations. A $60,000 grant from MCubed, U-M's one-of-a-kind seed
grant program, funded a collaboration between Lin and Cardinale that
yielded vital preliminary data that was included in the National Science
Foundation proposal.

"If, as we propose, it is possible to engineer naturally diverse
communities of algae to enhance the efficiency, yield and stability of
yields, then the development of multispecies photosynthetic
biorefineries would indeed represent a 'win-win' scenario for
biodiversity conservation and energy production in the next century,"
Lin said.

UC-Santa Barbara's Oakley is an evolutionary biologist who analyzes
differences in gene expression among species, and the functional
differences that result. He will lead the effort to use high-throughput
sequencing technologies to quantify every expressed gene in the various
algal combinations. That will enable the researchers to determine how
the production of biocrude correlates with the expression of any known
gene.

The four-year project will culminate in a conceptual design followed
by a life-cycle assessment. The conceptual design will examine all
aspects of a multispecies algal biorefinery, from algae cultivation to
biocrude production. It will determine the size needed for the facility
and will estimate the capital and operating costs, which in turn will
show the conditions required to make the biorefinery profitable.

The life-cycle assessment will measure the various environmental
impacts attributable to all activities related to the construction and
operation of a multispecies algal biorefinery—including emissions of
heat-trapping carbon dioxide gas largely responsible for human-caused
climate change. The results will then be compared to the impacts
resulting from the construction and operation of a single-species algal
biorefinery. Savage will work with researchers at Argonne National
Laboratory on the comparison.

If the four-year project proves fruitful, the researchers hope that
future funding could lead to the design and construction of prototypes
for a commercially viable multispecies algal biorefinery. But that day
is a long way off. For now, Cardinale and his colleagues are focused on
180 aquariums in the basement of the Dana Building.

"Do I feel like we're going to suddenly make algal biofuels
economically viable? No, of course not. That will take a decade-long
national research program and billions of dollars," Cardinale said. "But
I think this project might be an important piece of the puzzle that
eventually gets us there."


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