Heat- and oxygen-stable biocatalyst for hydrogen production

A selection from thermophilic bacteria

In the pursuit of highly stable [FeFe]-hydrogenase, the team started to search for [FeFe]-hydrogenases from thermophilic bacteria. Employing bioinformatics tools, they found the thermophilic bacterium Thermosediminibacter oceani that thrive around 70˚C and possesses a potentially interesting [FeFe]-hydrogenase. 

Understanding the high oxygen stability

After successful production and isolation of this new [FeFe]-hydrogenase, they observed its good thermostability and unprecedented oxygen-stability – it even survives after several days’ exposure to air. “It is so exciting to see this high stability,” says Subhasri Ghosh, the first author of the study. Using hydrogen production measurements, spectroscopy, site-directed mutagenesis, and machine learning-based structure prediction together with molecular dynamics computer simulations, the researchers gained detailed insights into the oxygen protection mechanism. They found that an additional sulfur-containing amino acid located near the catalytic center is crucial for oxygen stability. “Additionally, a cluster of hydrophobic amino acids influences protein dynamics and helps regulate oxygen resistance”, says Professor Lars Schäfer. “We are positive that some of these findings can be applied to other [FeFe]-hydrogenases and possible help in engineering more oxygen-stable [FeFe]-hydrogenases”, concludes Professor Thomas Happe from the Photobiotechnology group Ruhr University Bochum, who led the study.