The potential of using a two-stage hydrogen and methane fermentation of sugarcane juice was studied. The effects of pure and mixed culture as inocula on hydrogen production were compared. Additionally, the effects of pure culture inocula form, i.e., free cells or immobilized cells of Clostridium butyricum TISTR1032 was compared to different forms of mixed cultures, i.e., granules or suspended cells of heat-treated upflow anaerobic sludge blanket (UASB) granules. The hydrogenogenic effluents from all treatments were used as substrates to evaluate the potential of methane production by non-pretreated UASB granules. Results showed that a pure culture gave a higher hydrogen production potential and a shorter lag time in comparison to mixed cultures. Immobilized cells of C. butyricum TISTR1032 gave a hydrogen production potential that was 1.2 times higher than that of free cells. However, there was no significant difference in

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This study aimed to enhance hydrogen production from sugarcane syrup by biogas sparging. Two-stage continuous stirred tank reactor (CSTR) and upflow anaerobic sludge blanket (UASB) reactor were used to produce hydrogen and methane, respectively. Biogas produced from the UASB was used to sparge into the CSTR. Results indicated that sparging with biogas increased the hydrogen production rate (HPR) by 35% (from 17.1 to 23.1 L/L.d) resulted from a reduction in the hydrogen partial pressure. A fluctuation of HPR was observed during a long term monitoring because CO2 in the sparging gas and carbon source in the feedstock were consumed by Enterobacter sp. to produce succinic acid without hydrogen production. Mixed gas released from the CSTR after the sparging can be considered as bio-hythane (H2+CH4). In addition, a continuous sparging biogas into CSTR release a partial pressure in the headspace of the methane reactor. In consequent, the methane production rate is increased.

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