An international team of researchers has developed a new mechanism to protect enzymes from oxygen as biocatalysts in fuel cells. The enzymes, known as hydrogenases, are just as efficient as precious metal catalysts, but unstable when they come into contact with oxygen. They are therefore not yet suitable for technological applications. The new protective mechanism is based on oxygen-consuming enzymes that draw their energy from sugar. The researchers showed that they were able to use this protective mechanism to produce a functional biofuel cell that works with hydrogen and glucose as fuel.