Improved Hydrogen Production from Galactose Via Immobilized Mixed Consortia

In this study, a combined encapsulation and entrapment immobilization strategy was employed to enhance hydrogen production from sewage sludge containing mixed microbial cultures. The results showed that the hydrogen production rate (HPR) and hydrogen yield (HY) of immobilized cells were significantly higher than that of the suspended cells. The peak HPR and HY of 0.76 L/L-d and 1.20 mol/mol galactose_added attained with the immobilized cell system were comparable to that of the suspended cell system (HPR 0.62 L/L-d and HY 0.88 mol/mol galactose_added, respectively). The immobilized beads were also found to have efficient hydrogen production upon reuse for more than five cycles, with galactose removal > 85 % in all cases. Soluble metabolic product analysis revealed that fermentation followed a butyrate pathway and the major metabolites produced were acetate and butyrate. The peak total energy production rate and yield were 8.6 kJ/L-d and 308 kJ/mol _added, respectively.