[FeFe]-hydrogenases from green algae

Algal hydrogenases are among to the most efficient hydrogen (H₂) generating biocatalysts and use low-potential electrons from the photosynthetic light reactions. Thereby, photobiological H₂ evolution by eukaryotic microalgae represents a sustainable alternative to the energy intensive industrial production of H₂ based on fossil fuels. Novel algal hydrogenases are still being discovered and their biochemical and biophysical characterization has revealed unique features beneficial to overcome bottlenecks in photobiological H₂ production. Highly advanced techniques are available to study hydrogenases to atomic level accuracy. Yet, to benefit from these methods, one has to overcome the first and most fundamental obstacle, namely, obtaining sufficient amounts of active hydrogenase enzyme. The recombinant production of hydrogenases can be very challenging, so this chapter provides information and useful advice for the discovery, heterologous production, and analyses of hydrogenases from microalgae.