Hydrogen from Water in a Novel Recombinant Cyanobacterial System
Hydrogen is a clean alternative to gasoline and other fossil fuels that generates only water as a byproduct. Thus, it can significantly reduce emissions of both criteria air pollutants, and if it is not generated from fossil fuels, reduce emissions of greenhouse gases as well. The U.S. consumes about 20 million barrels of oil per day, much of which is used in the transportation sector. The heavy dependence on imported oil not only poses an adverse environmental impact, but it also renders the U.S. more vulnerable to energy supply disruptions.
Photobiological processes are attractive routes to renewable hydrogen production. With the input of solar energy, photosynthetic microbes such as cyanobacteria and green algae carry out oxygenic photosynthesis, extracting energy from water oxidation. The resulting energy can couple to a hydrogenase system yielding hydrogen. However, one major difficulty is that most hydrogen-evolving hydrogenases are irreversibly inhibited by oxygen, which is an inherent byproduct of oxygenic photosynthesis. The rate of hydrogen production is thus limited. Certain photosynthetic bacteria are reported to have an oxygen-tolerant evolving hydrogenase, yet these microbes do not split water, requiring other more expensive feedstocks.
The goal of our research is to develop a microbe that will form the basis for a viable, cost-effective, photobiological process to produce renewable hydrogen fuel. By combining the properties of two microorganisms cyanobacteria and photosynthetic bacteria we hope to develop a novel, hybrid microbe with two highly desirable traits not found together in nature: the ability to produce hydrogen in the presence of oxygen, using water as the feedstock.
Weyman PD, Vargas WA, Tong Y, Yu J, Maness PC, Smith HO & Xu Q. Heterologous Expression of Alteromonas macleodii and Thiocapsa roseopersicina [NiFe] Hydrogenases in Synechococcus elongatus. PLoS ONE. 2011. 6(5): e20126.
Weyman, PD, Smith HO & Xu Q. Genetic Analysis of the Alteromonas macleodii [NiFe]-Hydrogenase. FEMS Microbiology Letters. (In Press). DOI: 10.1111/j.1574-6968.2011.02348.x
Vargas, W. A., Weyman, P. D., et al.
[NiFe] Hydrogenase from Alteromonas macleodii With Unusual Stability In the Presence of Oxygen and High Temperature
Appl Environ Microbiol. 2011 Mar 01; 77(6): 1990-8.
Weyman, P. D., Vargas, W. A., et al.
Heterologous Expression of Alteromonas macleodii and Thiocapsa Roseopersicina [NiFe] Hydrogenases In Escherichia coli
Microbiology. 2011 Feb 24;
Maroti, G., Tong, Y., et al.
Discovery of a [NiFe]-hydrogenase In Metagenomic Sargasso Sea DNA: Cloning and Functional Analysis In Thiocapsa Roseopersicina
Appl Environ Microbiol. 2009 Jul 24;
U.S. Department of Energy