Image Credits: shutterstock.com/ElenaTlt
Hydrogen, that has only water and not carbon as waste, is so desirable as a fuel that Researchers are desperately trying to make it out of algae and make it scalable.
Early work, in 1939, was when Hans Gaffron at the University of Chicago first saw green algae create hydrogen; however, later Researchers have tried to set up the conditions to ensure its continuation.
For example, Anastasios Melis, PhD and colleagues at the University of California in Berkeley found, in 2000, that the algae Chlamydomonas reinhardtii could reliably release hydrogen rather than oxygen when sulfur was removed but light exposure was maintained.
Since then, systems are continually being devised to keep the hydrogen levels up.
For example, Researchers at Imperial College London have realized that for bioreactors to be made at an industrial scale, they need to be made into two joined reactors: one for algae growth and one for hydrogen production. This way the hydrogen side can receive fresh algae consistently while the old algae dies away. In a prototype, Researchers kept hydrogen for around 31 consecutive days at six times the rate than when they had used a single-chamber bioreactor. The team is now designing the reactors for future use, even on rooftops, by making them in plastic bags.
Like their counterparts, Researchers at Ruhr-Universität Bochum in Germany are analyzing the foundations of hydrogen creation from algae to better know how to amplify the effect. Using synthetic biology, they isolated the protein mechanisms in chloroplasts that create the hydrogen-producing enzyme, hydrogenase. The distinction was that the molecules necessary for the gas were not in the cytoplasm but only in the chloroplasts.
A necessary part found in the algae cell is something called the HYDA1 enzyme within which hydrogen production takes place. There, hydrogen comes about within clusters of four iron and four sulphur atom configurations and then a second set of two additional iron atoms binds to this for catalysis. Following this discovery, the team orchestrated the genome of the green algae to successfully produce bacterial hydrogenase.
Researchers in the public domain, including those at the U.S. Department of Energy’s Argonne National Laboratory, and in the private sphere such as Grow Energy are now working on the commercialization of biohydrogen looking at the different parts of algae and their different strains.
For example at the U.S. Energy Department's National Renewable Energy Laboratory (NREL) algae known as Chlorella and Scenedesmus were compared and staff found that Scenedesmus performed better with total fuel yields of 97 gallons gasoline equivalents (GGE) per ton of biomass. To bring down production costs, the lipid part of the algae was used along with the carbohydrates and proteins.
Another cost consideration of producing hydrogen from algae is ensuring multiple uses. Partnering with architecture group Ore Design + Technology, Grow Energy is building Hydral that, through genetically modified algae, produces hydrogen instead of oxygen from carbon dioxide over two-week-long conversion cycles. Algal biomass is recycled as a fertilizer or a product for biodiesel and petroleum gasoline off-site. Hydrogen can then be stored and used in fuel compatible vehicles, or in fuel cells for electricity and thermal heat energy.
One form of the Hydral is a modular 1 meter by 2 meter by 1 meter algae panel that can produce energy within a home.
Publicly traded Solarvest Bioenergy Inc. located in Canada is also refining a commercial platform for hydrogen production from Chlamydomonas reinhardtii. has demonstrated hydrogen production from a single batch culture for weeks rather than days at comparable rates of production to a two-bioreactor system. Interestingly, the system does not require the sulphur-starvation step. Another part of the company’s intellectual property is a method of altering the algae in such a way that its proteins and lipids can be extracted for use across industrial applications much like the choices being made at NREL.
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