Hydrogen production by Anabaena cylindrica: effects of varying ammonium and ferric ions, pH, and light.
Anabaena cylindrica sparged with argon gas produced H2 continuously for 30 days under limited light conditions (6.0 W/m2) and for 18 days under elevated light conditions (32 W/m2) in the absence of exogenous nitrogen. The efficiency of converting visible light energy (32 W/m2) into chemical energy that is trapped as H2 ranged between 0.35 and 0.85% (approximately 13 microliter of H2 per mg [drywt] per h). Ammonium additions (0.2 mM NH4+) at various times destabilized the system and eventually suppressed H2 production completely, as compared with the control. Cultures grown with 5.0 mg of Fe3+ per liter produced H2 at a rate about twice that of cultures with 0.5 mg of Fe3+ per liter. Cultures grown at pH 7.4 produced H2 at the same initial rates as cultures that were grown at pH 9.4; however, the latter cultures continued to produce H2 after CO2 deprivation.
D000114:Acetylene / Q000378:metabolism; D000643:Ammonium Chloride / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism; D008027:Light; D008717:Methionine Sulfoximine / Q000494:pharmacology; D010084:Oxidation-Reduction; D014871:Water Microbiology
D000643:Ammonium Chloride; D008717:Methionine Sulfoximine; D006859:Hydrogen; D007501:Iron; D000114:Acetylene