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In this study, a microbial consortium from an acid-treated rumen fluid was used to improve the yields of H2 production from paper residues in batch reactors. The anaerobic batch reactors, which contained paper and cellulose, were operated under three conditions: (1) 0.5 g paper/L, (2) 2 g paper/L, and (3) 4 g paper/L. Cellulase was added to promote the hydrolysis of paper to soluble sugars. The H2 yields were 5.51, 4.65, and 3.96 mmol H2/g COD, respectively, with substrate degradation ranging from 56 to 65.4 %. Butyric acid was the primary soluble metabolite in the three reactors, but pronounced solventogenesis was detected in the reactors incubated with increased paper concentrations (2.0 and 4.0 g/L). A substantial prevalence of Clostridium acetobutylicum (99 % similarity) was observed in the acid-treated rumen fluid, which has been recognized as an efficient H2-producing strain in addition to ethanol and n-butanol which were also detected in the reactors.

Waste paper was evaluated for hydrogen gas production by sequential dark fermentation and electrohydrolysis. Acid hydrolysed waste paper towel hydrolysate was first subjected to dark fermentation to determine the most suitable initial biomass concentration. The effects of initial biomass concentration was investigated at constant substrate concentration by varying the biomass concentration between 0 and 6 g/L and the most suitable hydrogen production was obtained at 0.10 g/L. Then effects of initial substrate concentration was investigated at 0.10 g/L initial biomass concentration by varying the glucose concentration between 5 and 40 g/L. 21.33 g glucose/L resulted in the highest hydrogen formation yield and rate in the second set of experiments. When the effluent of dark fermentation operated at optimum initial biomass and substrate concentration was subjected to electrohydrolysis the overall hydrogen production of the sequential process was 30.12 mL H2/mL. © 2015 Hydrogen Energy Publications LLC.