Will Algae Fuel The Hydrogen Economy?

Posted on 29. Sep, 2009 by Ross in New Technologies

The potential of harvested algae in the fight against global warming is a step closer to yet another massive contribution.

Whilst algae biofuels are starting to garner massive amounts of venture capitalism, and other potential applications such as algae batteries start to emerge from the depths of science fiction to become viable low-tech contenders to lithium batteries, a research collaboration between British and German universities have brought science a step closer to using algae farms to create hydrogen gas, publishing their findings in this week’s Journal of the American Chemical Society.

Cheaper, less energy-intensive production of hydrogen gas is one of the main hurdles in the way of realising the creation of a hydrogen economy - a system where hydrogen fuel cells are the primary source of energy most of the applications currently powered by oil, such as replacing combustion engines to create hydrogen-powered cars.

Algae produce small amounts of hydrogen as a by-product of photosynthesis (the process whereby algae and plants harness sunlight to create food). The hopes of the researchers is to boost the photosynthetic process of specific species of algae such as Chlamydomonas reinhardtii so that the organisms produce more hydrogen gas.

By using electrochemical kinetic experiments, the researchers analysed how the structure of the specific enzyme which was responsible for the algae’s production of hydrogen lost it’s potency in the presence of oxygen, isolating the mechanism of the attack. Speaking about the research, Professor Fraser Armstrong from Oxford University’s Department of Chemistry said:

The hydrogen-producing enzyme found in green algae, known as an iron-iron hydrogenase, has evolved a structure that makes it particularly susceptible to attacking oxygen molecules. Because oxygen is a major by-product of the hydrogen-making photosynthetic process in such organisms, the build-up of oxygen, which rapidly attacks the active site of the enzyme, quickly brings the hydrogen-making process to an irreversible halt. Our work has revealed the mechanism of this process.

By doing so, it gives scientists the opportunity to explore structures which are more resistant to attack by oxygen, either by genetically engineering algae to tweak the enzyme structure, or to transfer more oxygen-resistant enzyme genes from other algae or phytoplankton species.

This kind of approach is very different from earlier avenues of enquiry: in 2007 an American group of researchers at the University of California at Berkeley had been approaching the problem from an alternative angle. Aware that sunlight entering algae tanks can only permeate so far, they made headway in reducing the amount of chlorophyll - the primary active sun-harnessing component of algae - present in each algae cell. By doing so, sunlight was able to penetrate further into the culture, activating a greater number of algal cells into simultaneously generating hydrogen and increasing the hydrogen yield as a result.

Image by Ross Tucknott @ Flickr

Will algae be able to meet the demands of the future hydrogen economy? Have your say in the comments below…