High‐Throughput Screening of Catalytic H 2 Production

Hydrogenases, ferredoxins, and ferredoxin‐NADP + reductases (FNR) are redox proteins that mediate electron metabolism in vivo, and are also potential components for biological H 2 production technologies. A high‐throughput H 2 production assay device (H 2 PAD) is presented that enables simultaneous evaluation of 96 individual H 2 production reactions to identify components that improve performance. Using a CCD camera and image analysis software, H 2 PAD senses the chemo‐optical response of Pd/WO 3 thin films to the H 2 produced. H 2 PAD‐enabled discovery of hydrogenase and FNR mutants that enhance biological H 2 production is reported. From a library of 10 080 randomly mutated Clostridium pasteurianum [FeFe] hydrogenases, we found a mutant with nearly 3‐fold higher H 2 production specific activity. From a library of 400 semi‐randomly mutated Oryza sativa FNR, the top hit enabled a 60 % increase in NADPH‐driven H 2 production rates. H 2 PAD can also facilitate elucidation of fundamental biochemical mechanisms within these systems.