Biohydrogen: International collaboration and Status & potential of using cyanobacteria

Abstract

Molecular hydrogen (H2) is an environmentally clean energy-carrier that may be a valuable alternative to the limited fossil fuel resources of today. Biological hydrogen production, the production of H2 by microorganisms, has been an active field of basic and applied research for many years. Realization of practical processes for photobiological hydrogen production from water using solar energy would result in a major, novel source of sustainable and renewable energy, without greenhouse gas emissions or environmental pollution. In the present communication, I will discuss present activities and achievements within the four subtasks of Annex 15, Photobiological hydrogen production, of the IEA Hydrogen Agreement; A?Light-driven Hydrogen Production by Microalgae B?Maximizing Photosynthetic Efficiencies C?Hydrogen Fermentations D?Improve Photobioreactor Systems for Hydrogen Production In N2-fixing cyanobacteria, H2 is mainly produced by nitrogenases, but its partial consumption is quickly catalyzed by a unidirectional uptake hydrogenase. In addition, a bidirectional enzyme may also be present (2, 3). I will summarize present knowledge focusing on recent advances using molecular techniques, outline strategies for improving the capacity of H2-production, and discuss recent achievements using genetically modified cyanobacteria in a small scale photobioreactor.