Electron highway for hydrogen and carbon dioxide storage discovered
FRANKFURT/MARBURG/BASEL. In 2013, a team of microbiologists led by Professor Volker Müller of Goethe University Frankfurt discovered an unusual enzyme in heat-loving (thermophilic) bacteria: hydrogen-dependent CO. 2 HDCR reductase. It produces formic acid (formic) from hydrogen gas (H 2 ) and carbon dioxide (CO 2 ), and in the process, hydrogen transfers electrons to carbon dioxide. This makes HDCR the first known enzyme to directly utilize hydrogen. On the other hand, all the enzymes known to date that produce formic acid took a detour: they obtained electrons from soluble cellular electron transfer agents, which for their part accepted electrons from hydrogen with the help of other enzymes. The bacterium Thermoanaerobacter kivui thrives away from oxygen, for example in the deep ocean, and uses CO 2 and hydrogen to produce cellular energy. HDCR from Thermoanaerobacter kivui consists of four protein modules: one that cleaves hydrogen, one that produces formic acid and two small