A strain HN001 was shown to be effective in hydrogen production. In this study, the effects of operational conditions on hydrogen production were investigated using a bioreactor with immobilized supporter. The characteristics of Immobilization were figured out in case of continuous cultivation.
Saran fiber, saran mesh, polypropylene nonwoven and polyethylene nonworen were used as a sample of selectable supporter for immobilization. A cylindrical vessel (1.1 L) made from acrylic plastic was used as a cultivation tank. Temperature and pH of the cultivation were kept constant at 47 °C and 6.0, respectively. A molasses produced from a sugar plant was used as a sample. The sugar concentration of molasses was adjusted from 5 g-glucose L^-1 to 50 g-glucose L^-1, while HRT was controlled at 1.5 - 2.5 h.
H₂ production rate decreased significantly with increasing sugar concentration. It is assumed that the molasses included many minerals such as Na, K, Ca, etc. and the minerals restrained bacteria from growth. From the results of cultivation for 1 week, the immobilization on saran fiber formed many layers. The bacterial concentration of immobilizing fiber was 9.4 g per a fiber (200 mm). Saran fiber was an effective supporter for immobilization of the strain HN001. the maximum H₂ yield was 2.5 mol-H₂ mol-glucose^-1 under the sugar concentration of 5 g L^-1 and HRT of about 2.5 h. The maximum rate of H₂ production was 2.4 L-H₂ h^-1 L-culrute^-1 under the sugar concentration of 50 g L^-1 and HRT of about 1.5 h.