Growth and hydrogen production by Chlorella vulgaris Pa-023 under sulfur and nitrogen deprivation

The photodependent production of hydrogen (H2) as a promising source of renewable energy is currently of great interest. Green algae carry out photoproduction of H2 associated with electron transport during photosynthesis and catalyzed by [Fe]-hydrogenase, which is sensitive to oxygen and is inactivated by water photolysis. The issue of incompatibility between water photolysis and hydrogenase can be solved by creating deprivation of nutrients such as nitrogen and sulfur. The results have shown that H2 generation by Chlorella vulgaris Pa-023 is stimulated 2.5 times by sulfur deprivation and 2.7 times by nitrogen deprivation compared to algae grown on a complete Tamiya medium. The use of a specific inhibitor of PS II, DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea), demonstrated that during nutrient deprivation in algae operates a PS II-dependent pathway of H2 generation. Thus, sulfur and nitrogen deprivation stimulates photoproduction of H2 by C. vulgaris.