초록
To identify optimal hydrogen production conditions using growing cultures of Rhodobacter sphaeroides DSM 158 the effects of varying the reactor's volumetric power input (0.01-1.4kWm<SUP>-3</SUP>) and irradiation intensity (5-2500Wm<SUP>-2</SUP>) were investigated in batch and continuous production modes. Irradiation intensity had a greater effect on hydrogen production than volumetric power input. Hydrogen production and photofermentative biomass formation were maximized by irradiation at 2250Wm<SUP>-2</SUP> with a volumetric power input of 0.55kWm<SUP>-3</SUP>. The bacterial dry weight (2.64gL<SUP>-1</SUP>) and rate of hydrogen production (195mLL<SUP>-1</SUP>h<SUP>-1</SUP>) achieved under these conditions were greater than any that have previously been reported for batch-mode hydrogen production by R. sphaeroides. Continuous mode experiments (D=0.1h<SUP>-1</SUP>) yielded a bacterial dry weight, hydrogen production rate, productivity and hydrogen yield of 2.35+/-0.18gL<SUP>-1</SUP>, 165+/-6.2mLL<SUP>-1</SUP>h<SUP>-1</SUP>, 3.96LL<SUP>-1</SUP>d<SUP>-1</SUP> and 36.6%, respectively.