Biohydrogen production by microalgae isolated from the rice paddle field in Thailand

Hydrogen produced by cyanobacteria and green algae is a very interesting energy carrier because it is produced by a photosynthetic pathway using sunlight as an energy  source. In this study, 59 cyanobacterial and green algal strains were isolated from soil and water sources of rice paddle field in Thailand. Out of them, 9 cyanobacterial isolates and 9 green algal isolates were purified. Among them, unicellular cyanobacterial isolate AngS1 showed the highest H 2 production rate. Its highest H 2 production rate of 389.630±72.084 nmolH 2 mg chl -1 h -1 was found in cells grown in BG11 for 1 week followed by incubating  cells in BG11 0 for 24 hours and adaptation under dark anaerobic condition for 2 hours. The optimal concentrations of glucose, MgSO 4 .7H 2 O and Fe 3+ for H 2 production rate were 0.189 mmolC L -1 , 3 mM, and 20 μM, respectively. The highest H 2 accumulation of 4,174.364±278.324 nmolH  2 mg chl -1 was obtained when incubating cells in the optimal  medium for 11 days.