How Salmonella oxidises H2 under aerobic conditions

► Molecular hydrogen is an important energy source during prokaryotic respiration. ► Salmonella can utilise hydrogen as an electron donor for aerobic respiration. ► We use genetic engineering to isolate the Salmonella [NiFe] hydrogenase, Hyd-5. ► We use protein film electrochemistry to show Hyd-5 activity is oxygen-tolerant. ► We use EPR spectroscopy to classify Hyd-5 as an oxygen-tolerant [NiFe] hydrogenase