Journal of Power Sources, Vol.289, 26-33, 2015
Electricity and H-2 generation from hemicellulose by sequential fermentation and microbial fuel/electrolysis cell
Electricity and hydrogen generation by bacteria Geobacter sulfurreducens in a dual-chamber microbial fuel/electrolysis cell following the fermentation of hemicellulose by bacteria Moorella thermoacetica was investigated. Experimental results showed that 10 g l(-1) xylose under 60 degrees C was appropriate for the fermentation of xylose by M. thermoacetica, yielding 0.87 g-acetic acid per gram of xylose consumed. Corncob hydrolysate could also be fermented to produce acetic acid, but with lower yield (0.74 g-acid per g-xylose). The broths of xylose and corncob hydrolysate fermented by M. thermoacetica containing acetic acid were fed to G. sulfurreducens in a dual-chamber microbial fuel/electrolysis cell for electricity and hydrogen generation. The highest open-circuit cell voltages generated were 802 and 745 mV, and hydrogen yields were 41.7 and 23.3 mmol per mol-acetate, in xylose and corncob hydrolysate fermentation broth media, respectively. The internal resistance of the microbial fuel/electrolysis cell fed with corncob hydrolysate fermentation broth (3472 Omega) was much higher than that with xylose fermentation broth (1993 Omega) or sodium acetate medium (467 Omega), which was believed to be the main cause of the variation in hydrogen yield of the three feeding media. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Microbial fuel cell;Microbial electrolysis cell;Hemicelluloses;Acetic acid fermentation;Electricity generation;Bio-hydrogen production