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Dr. Maria Ghirardi is a principal scientist at NREL, a research associate professor at the Colorado School of Mines, and a Renewable and Sustainable Energy Institute (RASEI) Fellow. She is involved in both basic and applied research and has had extensive experience working with photosynthetic organisms.

Dr. Ghirardi's work at NREL involves photobiological hydrogen production and covers metabolic, biochemical, and genetic aspects of algal metabolism.

Dr. Ghirardi co-discovered a sulfur-deprivation process, which allows sustained hydrogen production from algae. In addition, her team identified three enzymes required for the assembly of [FeFe]-hydrogenases, which led to the development of a bacterial system for production of large quantities of active algal hydrogenase enzyme, a major breakthrough in research. They also initiated the use of molecular dynamics to create computational simulations of O2 and H2 gas diffusion through the hydrogenase enzyme, which led to the identification of two access pathways for O2 to the catalytic site of the enzyme.

This approach is now extensively used by groups in Europe to engineer oxygen tolerance into [NiFe]-hydrogenases. In collaboration with Dr. Matt Wecker from Genebiologics, Dr. Ghirardi developed a new selection method to isolate algal mutants with improved H2-producing capability, and made improvements in hydrogen photoproduction resulting from both physical and genetic manipulations. She also reported that algae can produce dramatically more hydrogen via the sun when the gas-phase to liquid-phase volume ratio in a bioreactor is increased. The observation helped bump up algae as major players in the search for the best alternative fuel of the future.

Currently, Dr. Ghirardi’s work involves a systems biology study of the role of the redox electron mediator ferredoxin in algal metabolism. Her group was able to express six ferredoxins in the bacterium Escherichia coli, which allowed them to purify each protein and biochemically/biophysically characterize each of them. When used in pull-down assays, they picked up different interactors, leading to hypotheses related to their physiological role in the alga that are being gradually tested in the laboratory.

Dr. Ghirardi has authored more than 120 publications, holds four U.S. patents, and has been featured as an invited speaker in many national and international conferences.

Areas of Expertise

  • Photosynthesis: electron transport, regulation, energy transduction, ferredoxins, in vivo measurements
  • Biohydrogen: algal hydrogenases, photoproduction, pathways, applications
  • Chlamydomonas: physiology, molecular engineering, biofuel pathways, photobioreactors
  • Algal biofuels production; expression of heterologous proteins/pathways


  • University of California, Berkeley: Ph.D. in Comparative Biochemistry, 1988. Graduate advisor: Dr. Anastasios Melis
  • University of California, Berkeley: M.A. in Comparative Biochemistry, 1983. Advisor: Dr. Anastasios Melis
  • University of California, Berkeley: B.S. in Bioenergetics, 1981
  • School of Medicine, University of São Paulo, São Paulo Brazil. 1972–1975

Associations and Accreditations/Memberships

  • NREL Fellow, 2013–present
  • Member of RASEI's Executive Committee, 2011–2013
  • Renewable and Sustainable Energy Institute (RASEI) Fellow, 2010–present


  1. "Oxygen-Resistant Hydrogenases and Methods for Designing and Making Same," U.S. Patent number 8,663,958 (2014)
  2. "Multi-Stage Microbial System for Continuous Hydrogen Production," WO 2005/042694 A2, provisional patent granted (2010)
  3. "Hydrogen Production Using Hydrogenase-Containing Oxygenic Photosynthetic Organisms," U.S. Patent number 6,989,252, (2006)
  4. "Process for Selection of Oxygen-Tolerant Algal Mutants that Produce H2 under Aerobic Conditions," U.S. Patent number 5,871,952 (1999)

Featured Publications

  1. Boehm, M., Alahuhta, M., Mulder, D.W., Peden, E., Long, H., Brunecky, R., Lunin, V.V., King, P.W., Ghirardi, M.L. and Dubini, A. (2015). "Crystal structure and biochemical characterization of Chlamydomonas FDX2 reveal two residues that, when mutated, partially confer FDX2 the redox potential and catalytic properties of FDX1." Photosynth. Res, in press.
  2. Xiong, W., Lee, T.C., Rommelfanger, S., Gjersing, E., Cano, M., Maness, P.C., Ghirardi, M. and Yu, J. (2015). "The phosphoketolase pathways in the central carbon metabolism of cyanobacteria." Nature Plants, in press.
  3. Wecker, M. and Ghirardi, M. (2014). "High-throughput biosensor discriminates between different algal H2-photoproducing strains." Biotechnology and Bioengineering. (111:7): pp. 1132-1340.
  4. Peden, E., Boehm, M., Mulder, D., Davis, R., Old, W., King, P., Ghirardi, M. and Dubini, Al. (2013). "Identification of Global Ferredoxin Interaction Networks in Chlamydomonas reinhardtii." The Journal of Biological Chemistry. (288); pp. 35192-35209.
  5. Wecker, M., Meuser, J., Posewitz, M. and Ghirardi, M. (2011). "Design of a new biosensor for algal H2 production based on the H2-sensing system of Rhodobacter capsulatus." International Journal of Hydrogen Energy. (36:17); pp. 11229-11237.
  6. Jorquera, O., A. Kiperstok, E.A. Sales, M. Embirucu, and M.L. Ghirardi. (2010). "Comparative energy life-cycle analyses of microalgal biomass production in open ponds and photobioreactors." Bioresource Technol. (101:4); pp. 1406-1413.
  7. Ghirardi, M.L., S. Kosourov, P.C. Maness, S. Smolinski and M. Seibert. (2010). "Algal Hydrogen Production," M. Flickinger, ed. Encyclopedia Industrial Biotechnology: Bioprocess, bioseparation, and Cell Technology. Vol. 1, John Wiley and Sons, Inc.; pp. 184-198.
  8. Ghirardi, M.L. and P. Mohanty. (2010). "Oxygenic Hydrogen Photoproduction Current Status of the Technology." Current Science (98); pp. 499-507.
  9. Eckert, C., A. Dubini, J. Yu, P. King, M. Ghirardi, M. Seibert, and P.C. Maness. (2010). "Hydrogenase genes and enzymes involved in solar hydrogen production," David Levin and Nuri Azbar, ed. State of the art and progress in production of biohydrogen. Bentham Science Publishers; pp. 8-24.
  10. Kosourov, S., M.L. Ghirardi and M. Seibert. (2011). "A truncated antenna mutant of Chlamydomonas reinhardtii can produce more hydrogen than the parental strain." Int. J. Hydrogen Energy (36); pp. 2044-2048.
  11. Ghirardi, M.L., L. Zhang, J.W. Lee, T. Flynn, M. Seibert, E. Greenbaum, and A. Melis (2000). "Microalgae: A Green Source of Renewable Hydrogen." (15); pp. 506-511.
  12. Kosourov, S.A.Tsygankov, M. Seibert. and M.L. Ghirardi (2002). "Sustained Hydrogen Photoproduction by Chlamydomonas reinhardtii Effects of Culture Parameters." Biotechnol (78); pp. 731-740.
  13. Forestier, M., King P., Zhang, L., Posewitz, M., Schwarzer S., Happe, T., Ghirardi, M.L., Seibert M. (2003). "Expression of two [Fe]-hydrogenases in Chlamydomonas reinhardtii under anaerobic conditions." European Journal of Biochemistry (270); pp. 2750-2758.
  14. Posewitz, M.C., King, P.W., Smolinski, S.L., Zhang, L., Seibert, M., and Ghirardi, M.L. (2004). "Discovery of Two Novel Radical S-adenosylmethionine Proteins Required for the Assembly of an Active [Fe] hydrogenase." J. Biol. Chem. (279); pp. 25711-25720.
  15. Posewitz, M. C.; Smolinski, S. L.; Kanakagiri, S.; Melis, A.; Seibet, A.; Ghirardi, M. L. (2004). "Hydrogen Photoproduction Is Attenuated by Disruption of an Isoamylase Gene in Chlamydomonas reinhardtii." Plant Cell (16:8); pp. 2151-2163.
  16. Ghirardi, M.L., King, P.W., Posewitz, M.C., Maness, P.C., Fedorov, A., Kim, K., Cohen, J., Schulten, K., and Seibert, M. (2005). "Approaches to developing biological H(2)-photoproducing organisms and processes." Biochem Soc. Trans. (33); pp. 70-72.

View NREL Publications for Maria Ghirardi.

Awards and Honors


  • NREL Staff Award for outstanding performance, 2003
  • Director's Award for outstanding contribution to DOE's Hydrogen Program, 2000


  • 2016 Fellow and Principal Scientist – American Association for the Advancement of Science (AAAS)
  • US DOE Office of Sciences award for outstanding student mentor, 2003
  • Kavli Frontiers of Science Fellow, November 2006
  • HENAAC (Hispanic Engineer National Achievement Award Corporation) Award for Outstanding Achievement, 2005
  • Glenn award, American Chemical Society, Fuels Division, for the best work presented during the New Orleans, Louisiana, meeting, August 1999

Invited Talks (Selected)

  • 16th International Biotechnology Symposium, Fortaleza, Brasil, 2014
  • Chair of Gordon Conference's session on Hydrogen Production, 2012
  • Bioenergy Conference in Paris, France, 2012
  • International Hydrogenase Conference, Sweden, 2010
  • Invited participant in DOE's Office of Science workshop on "Photosynthetic Efficiency," 2009
  • Microbial Genomics meeting in Lake Arrowhead, 2008
  • "A procura do Inesgotavel" event in Lisbon, Portugal, 2008
  • International Chlamydomonas Conference in France, 2008
  • Organizer of the International Hydrogenase Conference, Breckenridge , CO, 2007
  • Inaugural Gordon Conference on Renewable Fuels, Ventura, CA, 2006
  • Pacific Rim BIO conference, 2006
  • Session chair at the Western Photosynthesis Conference, 2006
  • Photosynthesis Gordon Conference, 2005
  • 7th International Hydrogen Conference, Reading, England, 2004
  • Boden Conference on Artificial Photosynthesis, Australia, 2003