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Hydrogen Production by Cyanobacteria

Hydrogen Production by Cyanobacteria

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Hydrogen Production by Cyanobacteria

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  1. Hydrogen Production by Cyanobacteria Dr. Teresa Thiel University of Missouri – St. Louis

  2. Light micrograph of filaments of Anabaena sp. with heterocysts

  3. Functions of heterocysts and vegetative cells

  4. Expression of nitrogen fixation genes only in heterocysts Green cells are heterocysts that are able to fix nitrogen and make hydrogen. Red cells are vegetative cells that cannot fix nitrogen and make hydrogen. Arrows indicate heterocysts identified by brightfield microscopy. Bar=10 mM

  5. Nitrogen fixation and hydrogen production in heterocysts

  6. Schindelin, H.,Kisker, C.,Schlessman, J.L.,Howard, J.B.,Rees, D.C. Nature 387:370-376 , 1997.

  7. Nitrogenase

  8. Building the dinitrogenase components- alpha

  9. Building the dinitrogenase component and now beta

  10. Building the dinitrogenase component - the second alpha

  11. Building the dinitrogenase component- and the second beta

  12. Adding the dinitrogenase reductase components the first of four subunits

  13. Adding the dinitrogenase reductase components - the second

  14. Adding the dinitrogenase reductase components - the third

  15. Adding the dinitrogenase reductase components the fourth

  16. Half of one nitrogenase molecule with both dinitrogenase and dinitrogenase reductase components

  17. The other half of one nitrogenase molecule with both dinitrogenase and dinitrogenase reductase components

  18. Building half of one nitrogenase molecule - starting with the dinitrogenase reductase components

  19. Building half of one nitrogenase molecule - starting with the dinitrogenase reductase components

  20. Building half of one nitrogenase molecule - adding the dinitrogenase components

  21. Half of Nitrogenase Finishing half of one nitrogenase molecule - adding the second dinitrogenase component

  22. 8 [H+ + e-] Reduces nitrogenase reductase Reduced nitrogenase reductase

  23. N N 8 [H+ + e-] Reduces nitrogenase reductase

  24. Functions of heterocysts and vegetative cells

  25. Anabaena produces hydrogen in a bioreactor Modified from Lindberg, P. Cyanobacterial Hydrogen Metabolism. Dissertation. University of Uppsala.2003.

  26. H2 fueling station http://www.actransit.org/environment/hyroad_richmond.wu

  27. Engineer nitrogenase to make more hydrogen

  28. Engineer heterocysts to express an efficient hydrogenase CP1 hydrogenase from Clostridium pasteurianum http://www.chemistry.montana.edu/~john.peters/gallery/structure1.html

  29. Engineer a strain with a very high frequency of heterocysts A high frequency of heterocysts as depicted here (artistic rendering, not actual photo) could allow cultures to produce large amounts of hydrogen using nitrogenase or hydrogenase.

  30. Advantages of Anabaena system • Requires only sunlight, air and water to grow and produce hydrogen • In contrast to other algal systems, it produces hydrogen in cells growing in air • No fossil fuels are required and oxygen is the only byproduct • Has been demonstrated to produce ¼ of the volume of a bioreactor of hydrogen per day (Tsygankov, A. A., et al. Biotechnol. Bioeng. 80, 777, 2002)

  31. N N 8 [H+ + e-] Reduces nitrogenase reductase Dinitrogenase reduces dinitrogen to ammonia and hydrogen