Light-powered, bacterial enzyme-containing nanoparticles that release hydrogen from water could lead the way to new strategies for generating the energy-rich gas. The lack of low-cost ways to create hydrogen gas is one of the main barriers to the dream of economies fuelled by hydrogen not oil.
Light-powered, bacterial enzyme-containing nanoparticles that release hydrogen from water could lead the way to new strategies for generating the energy-rich gas.
The lack of low-cost ways to create hydrogen gas is one of the main barriers to the dream of economies fuelled by hydrogen not oil.
A class of enzymes called hydrogenases are used by organisms to convert hydrogen ions to hydrogen gas during anaerobic - without oxygen - respiration. These enzymes have long interested chemists searching for alternatives to existing, expensive, platinum-catalysed hydrogen generation.
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The metal-containing enzymes are all crippled in varying degrees by the presence of oxygen and are also damaged by the very hydrogen they produce. That makes them difficult and expensive to use on industrial scales, says chemist Erwin Reisner, at Oxford University in the UK.
Bacterial gift
Now Reisner and colleague Fraser Armstrong have discovered that one bacterial hydrogenase is much more resistant to both gases.
The nickel, iron and selenium-rich enzyme, first isolated by Juan Fontecilla-Camps at the University of Joseph Fourier in Grenoble, France, is produced by a sulphate-reducing bacterium.
Its efficiency is relatively unaffected by the presence of hydrogen gas, and it continues to work even if the surrounding air contains 1% oxygen by volume - ordinarily even a few parts per million of oxygen would block hydrogenase activity.
The new enzyme also binds strongly to titanium dioxide nanoparticles, making it easy to produce a kind of light-powered, hydrogen-generating dust.
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