抄録
The effects of inoculum on the characteristics of thermophilic hydrogen fermentation were investigated by performing a long-term continuous experiment lasting more 50 days. Continuous hydrogen fermentation of starch was conducted under thermophilic condition (55°C) by using five types of inoculum, including thermophilically digested sludge of activated sludge, cattle manure and sewage sludge, compost, and thermophilic acidogenic sludge. Five chemostat-type reactors were operated at an HRT (hydraulic retention time) of 24h. Stable hydrogen production was achieved in each culture without any methane production during the long-term continuous experiment. The highest hydrogen yield (2.32 mol H2/mol hexose converted) was obtained by thermophilically digested sludge of activated sludge. The thermophilic hydrogen fermentation of starch by thermophilically digested sludge of activated sludge was expressed using the following stoichiometric equation : starch → 2.32n H2 + 2.14n CO2 + 0.5n acetate + 0.63n butyrate + 0.11n biomass (C5H9O3N).
