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Contract No. DE-AC36-08GO28308

Establishment of a Bioenergy 

Focused Microalgae Strain 

Collection Using Rapid, HighThroughput Methodologies

Cooperative Research and Development 

Final Report

CRADA Number: CRD-07-248

NREL Technical Contact: Philip T. Pienkos

CRADA Report

NREL/TP-7A10-59229

November 2013
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Cover Photos: (left to right) photo by Pat Corkery, NREL 16416, photo from SunEdison, NREL 17423, photo by Pat Corkery, NREL 

16560, photo by Dennis Schroeder, NREL 17613, photo by Dean Armstrong, NREL 17436, photo by Pat Corkery, NREL 17721.

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This report is available at no cost from the 

National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Cooperative Research and Development Final Report

In accordance with Requirements set forth in Article XI.A(3) of the CRADA document, this document is 

the final CRADA report, including a list of Subject Inventions, to be forwarded to the Office of Science 

and Technical Information as part of the commitment to the public to demonstrate results of federally 

funded research.

CRADA Number: CRD-07-248

CRADA Title: Establishment of a Bioenergy-Focused Microalgae Strain Collection Using 

Rapid, High-Throughput Methodologies

Parties to the Agreement: Colorado Center for Biorefining & Biofuels (C2B2)

Joint Work Statement Funding Table showing DOE Commitment:

Estimated Costs NREL Shared Resources

Year 1 $ 00.00

Year 2 $ 00.00

Year 3 $ 00.00

TOTALS $ 00.00

Abstract of CRADA Work:

This project is part of the overall effort by and among NREL, Colorado State University, University of 

Colorado, and Colorado School of Mines known as the Colorado Center for Biorefining and Biofuels. 

This is part of a larger statewide effort provided for in House Bill 06-1322, establishing a Colorado 

Collaboratory that envisions these four institutions working together as part of the state’s energy plan.

This individual project with Colorado School of Mines is the first of many envisioned in this overall 

effort. The project focuses on development of high throughput procedures aimed at rapidly isolating and 

purifying novel microalgal strains (specifically green alga and diatoms) from water samples obtained 

from unique aquatic environments.

Summary of Research Results:

A promising renewable energy scenario involves using photosynthetic microalgae for the production of 

biomass that can be converted into fungible, energy-dense fuels. Microalgae transform the energy in 

sunlight into a variety of storage products, including triacylglycerols, which can be readily transformed 

into diesel fuel surrogates. To develop an economically viable algal biofuels industry, it is critical to 

maximize the accumulation of targeted bioenergy carriers in selected feedstock strains.

In an effort to identify promising production isolates we developed, evaluated, and optimized 

contemporary high-throughput cell-sorting techniques to establish a collection of microalgae isolated 

from highly diverse ecosystems near geographic areas that are potential sites for large-scale algal 

cultivation in the Southwest United States. These efforts resulted in the isolation of 360 distinct 
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National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

microalgal strains. We have conducted initial screening studies of the culture collection to identify 

important biofuel phenotypes including neutral lipid accumulation and rapid growth rates. As part of this 

undertaking we determined suitable cultivation media and evaluated cryopreservation techniques critical 

for the long-term storage of the microorganisms in this collection. This rich source of biodiversity 

represents a valuable resource that can be leveraged for the selection of promising bioenergy feedstock 

strains, as well as for providing fundamental advances in our understanding of photoautotrophic diversity, 

biology, and metabolism.

In subsequent work, we developed a small scale photobioreactor system to allow us to grow multiple 

strains in the light under controlled conditions (including air and CO2 inputs) to evaluate these strains for 

growth and lipid productivity. One hundred promising strains were chosen for testing and 74 provided 

enough biomass after 15 days of cultivation for analysis of dry weight and lipid content (by fatty acid 

methyl ester (FAME) concentration. Cells at this point in the growth phase were believed to be nutrient 

replete and therefore expected to have high lipid content. The figure below summarizes the relationship 

between growth rate (gdcw/L at 15 days) and lipid content.

This work was discontinued due to lack of follow on funding. We have attempted to market the culture 

collection in various partnership efforts and have included it as an aspect for a proposal to the U.S. 

Department of Energy, with no success. We have attempted to revive strains from cryopreservation from 

time to time with variable results. It will require further funding to determine the viability of all of the 

strains, and so at this point, we are uncertain of the future potential for this work.
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This report is available at no cost from the 

National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Subject Inventions Listing:

NREL Record of Invention No. 11-109

Report Date:

9/26/13

Responsible Technical Contact at Alliance/NREL:

Philip T. Pienkos, Principal Group Manager Analytical Chemistry and Life Sciences

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