The Biohydrogen team in the Swartz Lab focuses on developing Biotechnology-based solutions to the global energy problem. Specifically, we are interested in developing sustainable processes for the production of hydrogen from (1) Sunlight and (2) Biomass (see below).
This is an important problem: the current method for making hydrogen--steam reformation of natural gas--is energy-intensive and accounts for 2.3% of the total human emissions of carbon dioxide.
The Biohydrogen team currently consists of Kunal Mehta, Stacey Shiigi, Franklin Lu, Jamin Koo, Lilian De La Paz, Sylvie Liong, and Marcus Rohovie. Former members of the group include Marcus Boyer, James Stapleton, Jon Kuchenreuter, Phil Smith, and Alyssa Bingham.
Early research by our team focused on building methods to produce active [FeFe] hydrogenases and study their assembly. These proteins catalyze the interconversion of protons, electrons, and dihydrogen; they are especially oxygen-sensitive due their FeS chemistry.
- Kuchenreuther JM, George SJ, Grady-Smith CS, Cramer SP, Swartz JR. Cell-free H-cluster Synthesis and [FeFe] Hydrogenase Activation: All Five CO and CN Ligands Derive from Tyrosine. PLoS One 6, e20346 (2011) PMID 21673792
- Kuchenreuther JM, Grady-Smith CS, Bingham AS, George SJ, Cramer SP, Swartz JR. High-yield expression of heterologous [FeFe] hydrogenases in Escherichia coli. PLoS ONE 5, e15491 (2010). PMID 21124800
- Kuchenreuther JM, Stapleton JA, Swartz JR. Tyrosine, cysteine, and S-adenosyl methionine stimulate in vitro [FeFe] hydrogenase activation. PLoS ONE 4, e7565 (2009). PMID 19855833
- Boyer ME, Stapleton JA, Kuchenreuther JM, Wang CW, Swartz JR. Cell-free synthesis and maturation of [FeFe] hydrogenases. Biotechnol Bioeng 99, 59-67 (2008). PMID 17546685
- Boyer ME, Wang CW, Swartz JR. Simultaneous expression and maturation of the iron-sulfur protein ferredoxin in a cell-free system. Biotechnol Bioeng 94, 128-38 (2006). PMID 16570319
The first major goal of this research was the evolution of an oxygen-tolerant [FeFe] hydrogenase. This has proven to be extremely difficult; indeed many other research groups have tried this and been ultimately unsuccessful. However, our evolution methodology is different and has led to some level of success in this endeavor; however, much remains to be done to achieve this overall objective.
- Bingham AS, Smith PR, Swartz JR. Evolution of an [FeFe] hydrogenase with decreased oxygen sensitivity. International Journal of Hydrogen Energy (2011) doi:10.1016/j.ijhydene.2011.02.048
- Stapleton JA, Swartz JR. Development of an in vitro compartmentalization screen for high-throughput directed evolution of [FeFe] hydrogenases. PLoS ONE 5, e15275 (2010). PMID 21151915
- Stapleton JA, Swartz JR. A cell-free microtiter plate screen for improved [FeFe] hydrogenases. PLoS ONE 5, e10554 (2010). PMID 20479937
The vision is that such a hydrogenase, once evolved, would be used in a photosynthetic microorganism to produce hydrogen directly from sunlight and water. This would require metabolic engineering of an insulated electron transfer circuit from the photosystems to the hydrogenase. We are currently developing the tools to begin engineering this system.
A second project was begun in 2009 focusing on the production of hydrogen from biomass. The approach is to build a synthetic enzyme pathway that is able to produce hydrogen from NADPH; this pathway would then be coupled to the pentose phosphate pathway to enable hydrogen production from glucose (a proxy for biomass).
- Smith PR, Bingham AS, Swartz JR. Generation of hydrogen from NADPH using an [FeFe] hydrogenase. International Journal of Hydrogen Energy (2011) doi:10.1016/j.ijhydene.2011.03.172
Funding: We are grateful for funding from GCEP and the DOE