Biofuel Breakthrough Uses Algae To Create Hydrogen
A research group from the University of Turku, Finland, has discovered an efficient way for transforming solar energy into the chemical energy of biohydrogen through the photosynthesis of green algae that function as cell factories. Molecular hydrogen is regarded as one of the most promising energy carriers due to its high energy density and clean, carbon-free use.
During photosynthesis, green algae utilize harvested solar energy to split water, release oxygen into the atmosphere and produce biomass that functions as an excellent feed-stock in the blue biorefinery.
During photosynthesis, the green algae utilize harvested solar energy to split water, release oxygen into the atmosphere and produce biomass that functions as an excellent feed-stock in the blue biorefinery.
Green algae are also efficient biocatalysts and can transform solar energy and carbon dioxide directly into different valuable compounds, such as vitamins, antioxidants, polymers, and carbohydrates.
The leader of the research group, Yagut Allahverdiyeva-Rinne, Associate Professor of Molecular Plant Biology at the University of Turku said, “When algal cells are first incubated under anaerobic conditions in the dark and then exposed to light, they start producing hydrogen efficiently, but unfortunately only for a few seconds.”
For decades researchers have believed that the main obstacle to the longer-term hydrogen production by algae in light is the destruction of the hydrogenase enzyme, a key element in this process, which is caused by oxygen.
Senior Researcher Sergey Kosourov, a member of the research group explained, “Since algae constantly release oxygen during their photosynthesis that occurs simultaneously with the production of hydrogen, maintenance of anaerobic conditions in illuminated cultures has been particularly troublesome.”
The researchers at the University of Turku decided to apply the knowledge retrieved from the basic research on the photosynthesis of algae and established a new method for producing hydrogen that does not expose green algae to additional nutritional starvation and, thus, without applying any significant stress to the cells. The team’s research paper has been published in the journal Energy & Environmental Science. The researchers showed that the production of hydrogen could be significantly extended by simply exposing the anaerobic algal cultures to a train of strong yet short light pulses, which are interrupted by longer dark periods.
“Under these conditions, algal cultures exposed to sunlight do not accumulate oxygen in the medium. In addition, algae steer the electrons resulting from the decomposition of water and charged by sunlight into hydrogen production instead of biomass accumulation. The process lasts for, at least, several days and the maximum rate of the production of hydrogen occurs during the first eight hours,” Kosourov said.
The research indicated clearly that a major obstacle to efficient hydrogen production is not oxygen but a strong competition between two metabolic pathways: carbon dioxide fixation leading to the biomass accumulation and the hydrogenase enzyme catalyzing photoproduction of hydrogen.
Allahverdiyeva-Rinne noted, “The study opens up new possibilities for the construction of efficient living cell factories for the production of biofuels and different chemicals directly from sunlight, carbon dioxide and water. The research provides important information on how to avoid ‘wasting’ solar-driven energy in biomass production and how to apply this energy directly for the production of useful bio-products.”
The new method developed by the researchers is valuable both for the basic research of the photosynthesis of algae and for the research and development work of the industrial sector when producing new technologies for the large-scale production of carbon neutral biofuels.
It has been a while for seeing much action on the biofuel topics. The oil price collapse that is gradually ending and research funder’s choices in granting research dollars have slowed things down. These points and the less than stellar results from research so far has kept biofuels, aside from ethanol, way back in the pack of fuel competitors.
If this research can add to the value of algae production with hydrogen output plus other products perhaps the algae effort can get some more progress to marketing fuels. Its still a very long way to go.
By New Energy And Fuel
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