Water-splitting-based, sustainable and efficient H(2) production in green algae as achieved by substrate limitation of the Calvin–Benson–Bassham cycle

BACKGROUND: Photobiological H(2) production has the potential of becoming a carbon-free renewable energy source, because upon the combustion of H(2), only water is produced. The [Fe–Fe]-type hydrogenases of green algae are highly active, although extremely O(2)-sensitive. Sulphur deprivation is a common way to induce H(2) production, which, however, relies substantially on organic substrates and imposes a severe stress effect resulting in the degradation of the photosynthetic apparatus. RESULTS: We report on the establishment of an alternative H(2) production method by green algae that is based on a short anaerobic induction, keeping the Calvin–Benson–Bassham cycle inactive by substrate limitation and preserving hydrogenase activity by applying a simple catalyst to remove the evolved O(2). Cultures remain photosynthetically active for several days, with the electrons feeding the hydrogenases mostly derived from water. The amount of H(2) produced is higher as compared to the sulphur-deprivation procedure and the process is photoautotrophic. CONCLUSION: Our protocol demonstrates that it is possible to sustainably use algal cells as whole-cell catalysts for H(2) production, which enables industrial application of algal biohydrogen production. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-018-1069-0) contains supplementary material, which is available to authorized users.