A protective shield for catalysts sensitive to oxidative damage has been developed by an international team. The hydrogel coating was used in a proof of principle experiment to protect the hydrogenase enzyme from the green alga Chlamydomonas rheinhardtii. Such biological catalysts could be used in future as highly specific and efficient catalysts to replace costly and general precious metal catalysts, such as platinum and palladium for a wide range of reactions. Until now, their tendency to degrade has made them industrially untenable in many cases. The same protective coating might also assist in the development of new fuel cell technology where, again, a biocatalyst might be used instead of a metal. “In future, we will thus no longer have to pay attention to the robustness or suitable reactivation processes when developing catalysts for technical applications,” explains chemist Olaf Rüdiger of the Max Planck Institute for Chemical Energy Conversion. “We can focus solely on maximising the catalyst’s activity."