Relation between hydrogen production and photosynthesis in the green algae Chlamydomonas reinhardtii

Abstract: The modernized world is over-consuming low-cost energy sources that strongly contributes to pollution and environmental stress. As a consequence, the interest for environmentally friendly alternatives has increased immensely. One such alternative is the use of solar energy and water as a raw material to produce biohydrogen through the process of photosynthetic water splitting. In this work, the relation between H2-production and photosynthesis in the green algae Chlamydomonas reinhardtii was studied with respect to three main aspects: the establishment of prolonged H2-production, the involvement of PSII in H2-production and the electron pathways associated with PSII during H2-production. For the first time, this work reveals that PSII plays a crucial role throughout the H2-producing phase in sulfur deprived C. reinhardtii. It further reveals that a wave-like fluorescence decay kinetic, before only seen in cyanobacteria, is observable during the H2-producing phase in sulfur deprived C. reinhardtii, reflecting the presence of cyclic electron flows also in green algae.