It is known that microalgae under certain conditions are capable of producing molecular hydrogen by photosynthetic energy conversion. The importance of this form of energy due to the following: the presence of an unlimited source of energy - sunlight, excess substrate photolysis - water, high heating value of hydrogen, the possibility of process recovery, and finally the fact that the photochemical transformation of water to hydrogen takes place at normal temperature without the formation of toxic intermediate compounds. The main obstacle in achieving long photoevolution of hydrogen is the oxygen produced by photosynthesis. 10 years ago an approach to eliminate oxygen from the culture medium of algae by removing inorganic sulfur was proposed. In these circumstances it becomes impossible to update the photosynthetic systems, producing O2. After a short time (about 20 h) oxygen in the solution is completely exhausted, and begins the evolution of hydrogen. Microalgae culture without losing viability and when adding sulfur reverts to aerobic photosynthesis
This work is a first in Ukraine to study the ability of microalgae to provide molecular hydrogen from the photosynthetic conversion of light energy. The research objects were microalga from the collections of living cultures of the N.G. Kholodny Institute of Botany NAS Ukraine. It was selected strains for further study based on data determining the rate of light depended hydrogen evolution, the duration of the process, as well as the growth rate of the culture. A photobioreactor for the intensive cultivation of microalgae in a controlled environment was designed using red and blue LEDs. Methods of influence on the metabolism in the direction of increasing the yield of hydrogen developed were proposed. Conditions that cause induction of hydrogenase activity in cultures of microalgae were studied.
Keywords: hydrogen, photobioreactor, microalgae, photosynthesis, biophotolysis, carbon dioxide, biotechnology, Chlamydomonas reinhardtii