Exploration of photoautotrophic hydrogen production in Synechocystis sp. ATCC 27184

Abstract

Anthropogenic carbon dioxide emissions possess severe treats to Earth’s climate balance and warms the planet. In order to reverse this trend, conventional energy production from fossil fuels must be abandoned in near future. It is an urgent and critical need to shift towards low carbon intensive energy production technologies. While solar and wind energy mainly focus on electricity production, hydrogen technologies remains as notable energy carrier which requires more sustainable production methods. On this manner, innovative biofuel applications open new horizons. Cyanobacteria are alternative third generation biofuel resources for hydrogen technologies. Cyanobacterium Synechocystis sp. strain ATCC 27184 (also designated as PCC 6803 [N-1]) is known for its hydrogenase enzyme which is able to produce hydrogen gas by direct photolysis of water molecules. However, oxygen is a strong inhibitor for the enzyme. In this study, hydrogenase activity and total hydrogen gas production potential are explored in various growth media. Culture media BG- 11 is modified by removing nitrogen and sulfur nutrients separately. Plus, the effect of strong reducing agent sodium thioglycolate salt is investigated. Although sodium thioglycolate is effective in removing both dissolved oxygen and photosynthetic oxygen gas, hydrogenase activity is not significantly increased. Highest hydrogenase activity is observed in sulphur deprived medium. Direct hydrogen production is not observed in any of experimental media in the course of the study.