Researchers investigate hydrogen-producing algae farms
April 4, 2008 Here’s a futuristic, car-related technology you won’t see in the next summer sci-fi blockbuster: the algae-powered automobile. Some varieties of the unicellular plant are being tweaked to produce of hydrogen, which can be used to power efficient, environmentally clean vehicles. Researchers at the US Department of Energy’s Argonne National Laboratory believe that algae’s ability to grow pretty much anywhere will enable it to be the energy farm of the near future.
When deprived of sulfur, algae stops emitting oxygen, and the hydrogenase enzyme manufactures hydrogen gas at an efficiency level of 0.1%. Research into biological hydrogen production started around a decade ago, but only in the last few years have scientists begun to push algae to reach the golden efficiency level of 10-15%. Techniques used to stimulate extra hydrogen production have included genetic modification, shortening the chlorophyll stacks, and introducing copper. David Tiede, at the Argonne National Laboratory, plans to incorporate the hydrogenase enzyme into the photosynthetic protein framework.
“We believe there is a fundamental advantage in looking at the production of hydrogen by photosynthesis as a renewable fuel,” senior chemist David Tiede said. “Right now, ethanol is being produced from corn, but generating ethanol from corn is a thermodynamically much more inefficient process.”
Although alternative production methods using celluosic biomass are being investigated, ethanol production from food based crops faces major challenges in regard to deforestation and soaring food prices, which stem from its need for large amounts of farmable land. Algae, as anyone who has lived in a share-house knows, is not nearly as demanding. The plant can be grown in deserts, on rooftops, and in closed, portable photobioreactors. One model, outlined by the University of California, claimed that to displace gasoline use in the US, 25 000 square kilometers of algae farms, (situated on otherwise unusable land), would be required – less than a tenth of what the US devotes to growing soya.
“If you have terrestrial plants like corn, you are restricted to where you could grow them,” Tiede said. “There is a problem now with biofuel crops competing with food crops because they are both using the same space. Algae provides an alternative, which can be grown in a closed photobioreactor analogous to a microbial fermentor that you could move any place.”