Microbiologists have shed light on the structure of an enzyme that produces formic acid from molecular hydrogen (H2) and carbon dioxide (CO2). The enzyme of the bacterium Thermoanaerobacter kivui was discovered a few years previously by microbiologists, and the scientists have recently presented its potential for liquid hydrogen storage. The filamentous structure of the enzyme, now described at atomic level for the first time, acts like a nanowire and is evidently responsible for the extremely efficient conversion rates of the two gases.