Hydrogen & Fuel Cells
- Category: Hydrogen & Fuel Cells
08 Oct 2009
- Published on Thursday, 08 October 2009 13:05
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The hydrogen-producing green algae Chlamydomonas reinhardtii.
Scientists at the University of Oxford have discovered how oxygen stops green algae from producing hydrogen, which could give rise to working “solar H2-farms” where micro-organisms could be harnessed to produce hydrogen fuel from sunlight and water.
An international team from Oxford and universities in Germany reported their discovery in two papers, one in the journal JACS and the other in PNAS, published recently.
Scientists have long theorized that hydrogen could be produced from just sunlight and water. One option would be to use micro-organisms that are able to produce hydrogen as well as starch during photosynthesis, such as green algae.
Green algae have a hydrogen-producing enzyme known as iron-iron hydrogenase which has evolved a structure that makes its particularly susceptible to attacking oxygen molecules. Because oxygen is a major by-product of the photosynthetic process, the build-up of oxygen attacks the active site of the enzyme and brings the hydrogen-making process to a halt.
Yet while the research reported in PNAS shows just how destructive oxygen is to the enzyme powering green algae’s hydrogen-making process, the team’s research reported in JACS shows that similar hydrogenases produced by other micro-organisms may possess greater tolerance to oxygen, sufficient perhaps to survive in the presence of oxygen released during photosynthetic hydrogen production.
This knowledge could help devise new ways by which the problem of oxygen’s destructive effect on hydrogen-producing enzymes could be countered.
The team will shortly be publishing the results of similar research into nickel-iron hydrogenases, enzymes related to those that enable blue-green algae to produce hydrogen.
The research was carried out by an international team including Professor Fraser Armstrong, Gabrielle Goldet, Caterina Brandmayr, and Kylie Vincent from Oxford’s Department of Chemistry with researchers from Germany’s Ruhr Universität Bochum and Freie Universität Berlin.
- Katrice R. Jalbuena