Hydrogen-making algae’s ‘Achilles’ heel’ discovered
An international team of scientists from Oxford University and universities in Germany, report their findings in two articles, one in the JACS and one in the journal PNAS, published this week.
For years scientists have been interested in how that could potentially produce hydrogen from only sunlight and water for vehicles and other devices. One option is to use photosynthetic organisms that are capable of producing hydrogen as well as starch. Green algae are among the microorganisms that many have suggested that they could become living factories hydrogen.
“Hydrogen and the production of the enzyme is found in green algae, known as an iron-dehydrogenase, has developed a structure that makes it particularly susceptible to attack oxygen molecules,” said Professor Fraser Armstrong of the Oxford University Department of Chemistry, the author of both papers. “Because oxygen is an important product of the process of making hydrogen from these photosynthetic organisms, the accumulation of oxygen rapidly attacks the active part of the enzyme is rapidly making hydrogen for a halt irreversible. Our work has revealed the mechanism of this process. ”
The team used methods of electrochemical kinetics to determine the order of events in which oxygen attacks the active site of an iron-dehydrogenase is found in green algae Chlamydomonas reinhardtii. They combined their observations with data obtained from absorption spectroscopy X-ray. By measuring waves in the photoelectron energy spectrum of the enzyme in the X-ray bombardment were able to deduce the nature of the damage to the active side after the attack by oxygen.
However, while research published in PNAS shows how destructive oxygen and hydrogen is the green algal enzyme driving the adoption process, the team’s research shows that reported in JACS similar hydrogenases produced by other microorganisms have increased tolerance to oxygen, sufficient perhaps to survive in the presence of oxygen released during the photosynthetic hydrogen production.
Professor Armstrong said: “This shows that although you may have found a major barrier along a route to biological hydrogen production, this knowledge could help identify new routes in nature might suggest an answer to the problem of destructive effect of oxygen in the hydrogen producing enzymes.
The team will soon publish the results of similar investigations of nickel-iron hydrogenases, the enzymes related to allow blue-green algae to produce hydrogen.