Algae Research in Full Bloom at NREL
NREL, November 3, 2010
"In a test tube, vibrant green microalgae look fragile, but in reality getting
them to spill their lipid secrets to make renewable fuels is a challenge one
that researchers at the U.S. Department of Energy's (DOE) National Renewable
Energy Laboratory are tackling, again.
From 1978 to 1996, DOE funded NREL's study of microalgae under the Aquatic
Species Program. During that time, 3,000 algae strains were isolated from
various aquatic habitats. Roughly 50 caught the attention of researchers for
their potential use in producing transportation fuels.
Then in 1996, the price of oil bottomed out at roughly $20 a barrel. The
estimated cost of algae oil at the time was about $80 a barrel. With those price
factors and other budget pressures, DOE stopped funding the Aquatic Species
Program. Algae strains were sent to the University of Hawaii for safekeeping and
the NREL team summarized nearly 20 years of research in the program's Close Out
Report (A Look Back at the U.S. Department of Energys Aquatic Species Program:
Biodiesel from Algae http://www.nrel.gov/docs/legosti/fy98/24190.pdf).
Fast forward 10 years and the Energy Independence and Security Act of 2007
(EISA) is passed by Congress. The 2007 law required that the U.S. produce and
use 36 billion gallons of renewable fuels by 2022. EISA capped the use of starch
based ethanol at 15 billion gallons and called for the remainder to be made up
by "advanced biofuels" basically anything else.
Because of its past research, NREL was ahead of the curve. In 2006 an NREL
research team began seeking new funding for algae research. In a few short
years, the team raised more than $8 million.
NREL used some funding to retrace work in the old program by bio-prospecting for
new strains, but thanks to new technology, the work goes a lot faster.
"We've accumulated almost 400 different algal strains from differing
environments freshwater, brackish and saline," NREL Principal Group Manager Al
Darzins said. "Today we have higher throughput devices that allow us to process
samples very quickly. Think about it like using tweezers although it's a
little more complicated than that. We can actually sort and pick out, at will,
individual algae from the water sample and get a pure culture of a single strain
Once samples are collected, NREL is focused on understanding the biology of the
organisms. "If you don't understand the biology and how to grow them, how are
you ever going to grow them at a large scale and control them?" Darzins said.
NREL chose a strain of the algal species, Chlorella vulgaris, as its model
organism. Researchers are trying to get a complete view of its molecular biology
and biochemistry. In their opinion, it's a good study subject because it grows
quickly and makes a lot of oil.
But, one of the hard parts of dealing with algae is getting the oil out of the
cells this is especially true with Chlorella vulgaris. "We typically use some
sort of solvent but even that's not so easy and the cell wall can resist it,"
Principal Research Supervisor Phil Pienkos said. "NREL is working to find
enzymes that can help degrade the cell wall of algae and allow the solvents
access so we can more efficiently extract the oil."
According to Pienkos, if an enzyme is found that can easily break down the cell
wall, it might be possible to isolate the gene for that enzyme and engineer the
algae to produce that enzyme just before it is ready to harvest.
"NREL is looking at the metabolic engineering of algae but only to find out the
fundamentals of how these organisms tick," Darzins added. "We are not growing
genetically modified organisms outside the lab. By using them only in the
controlled laboratory setting, we think it will tell us quite a bit."
To accelerate the deployment of advanced biofuels, President Obama and Secretary
of Energy Steven Chu announced the investment of $800 million in new research on
biofuels in the American Recovery and Renewal Act. The announcement included
funds for research, development and deployment of commercial algae-to-biofuels
processes. Algenol was awarded $25 million to pilot a photo-bioreactor algal
biofuel system and NREL is working with this company to help them accelerate
"They have a unique technology using algae to convert carbon dioxide (CO2)
directly to ethanol," Pienkos said. "Their photo bioreactor system allows them
to continuously produce ethanol so they don't have to harvest algae."
NREL is working with Algenol on two fronts a techno economic and lifecycle
analysis of their production facility and evaluation of the algae for
sensitivity to components in the flue gases used to feed the algae.
Whether a company is striving to make ethanol, green diesel or even jet fuel
from algae, the key will be isolating the right algae from the pool of
thousands, if not hundreds of thousands of available strains in the environment.
Sorting through water samples looking for the right candidate for a project
consumes lots of money. NREL is solving that problem by using infrared light to
sort out the best oil-producing algae.
The process works by shining a broad spectrum light, with wavelengths ranging
from the visible to the infrared region of the spectrum, at the sample. Several
different detectors measure how much light is reflected versus how much was
absorbed by the sample. According to Laurens, different molecules in the algal
biomass will have different absorption peaks showing a "fingerprint" for the
algae. That fingerprint, along with a mathematical model, is then used to
estimate the oil content of that particular strain of algae.
Once an algal strain is selected, cultivated and the oils are finally harvested,
there are leftovers which are referred to as residual biomass. The other
question NREL researchers are tackling is what to do with the leftovers. Could
they be used to make ethanol or biogas?
"Algae has a lot of potential, and NREL has been doing a good job of not
subscribing to all of the hype," Darzins said. "We have been a credible advisor
to DOE, industry and the general research community. Our message has been that
for algal biofuels the potential is huge it could be a game changer. But, the
challenges are equally as daunting and boy, have we got our work cut out for
Dr. Ann C. Wilkie Tel: (352)392-8699
Soil and Water Science Department Fax: (352)392-7008
University of Florida-IFAS
P.O. Box 110960 E-mail: [log in to unmask]
Gainesville, FL 32611-0960
Campus location: Environmental Microbiology Laboratory (Bldg. 246).
BioEnergy and Sustainable Technology Society