Blue-green algae (which are not “true” algae but are cyanobacteria) are ubiquitous. They are found in most parts of the world, widespread especially in freshwater, marine, and terrestrial ecosystems. The bacteria have a number of interesting properties — one is to use the energy from that captured light, through the process of photosynthesis, to produce hydrogen.
The process of hydrogen generation (taking light from the sun and utilizing water) ticks the necessary boxes for a renewable form of energy. It is this process that researchers from the U.S. Department of Energy’s Pacific Northwest National Laboratory have been studying.
Studies have revealed Cyanothece 51142 to capable of tapping into an unusual source of energy to create hydrogen. The bacterium produces hydrogen by utilizing sugars stored-up during the organism’s growth. The bacterium also draws on sunlight, as a second source of energy, and utilizes water to produce hydrogen.
Trials have been undertaken using a specially equipped bioreactor. Control of the bioreactor was important given that the bacteria possess an enzyme called nitrogenase. When nitrogen is present, the enzyme processes inert atmospheric nitrogen (a process called nitrogen fixation.) However, when the nitrogen supply is limited, the bacterium produces hydrogen.
If photosynthesis and the hydrogen production by nitrogenase can be controlled in an optimal culture, then the bacterium can be used as a steady, low cost renewable source of energy.
The research findings are published in the journal Scientific Reports. The paper is titled “Multi-Omic Dynamics Associate Oxygenic Photosynthesis with Nitrogenase-Mediated H2 Production in Cyanothece sp. ATCC 51142.”