Cyanobacteria, formerly called “blue-green algae” are micro-organisms capable of producing under normal conditions, stocks of energy enabling them to survive under stress, such as during a prolonged time in the dark. This storage requires the presence of a molecular switch in an enzyme, ATPase. The removal of the latter would make it possible to use the excess energy for biotechnology, such as hydrogen production. Under the leadership of Matthias Rogner, researchers at the University of the Ruhr (North Rhine-Westphalia) applied to prove this theory. Their results, obtained in collaboration with a Japanese group of Tokyo Institute of Technology, was published in the magazine called “Journal of Biological Chemistry.”

ATP is the molecule that stores energy produced during photosynthesis and may need to be degraded by the enzyme ATPase, when the bacterium needs to use this energy. To protect the bacteria against stress situations, such as variations in brightness, the ATPase of the cyanobacterium has a small area that operates as a molecular switch. This prevents the ATP to be degraded too quickly under conditions of stress, such as during a prolonged dark period during which the process of photosynthesis can take place. The molecular switch prevents energy waste and the bacteria, creating a reserve of energy, these phases can withstand stress.

Matthias Rogner and his colleagues deleted the area acting as a molecular switch in the ATPase in cyanobacteria genetic modifications. The early assumptions were that the scientific development of cyanobacteria would be modified less efficiently. After observation, the results proved different. Bacteria have developed as usual in laboratory conditions (no light stress), but with a slightly lower stock of ATP resulting in a poorer ability to survive during long periods of darkness, unlike the cyanobacteria with the natural state. In theory, the excess energy produced from sunlight could be recovered for another application of biotechnology, such as hydrogen production by cyanobacteria in a bioreactor. This hydrogen would then be a clean and renewable energy carrier.

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