(752a) Recovery of Bioelectricity and Hydrogen from Biorefinery Effluents

Biomass conversion to biofuels can be achieved via biochemical and thermochemical processes at a process efficiency of 49-54%. A significant portion of the biomass is converted to byproducts and other compounds, some of which are inhibitory to the biofuel production processes. Water recycle is an important consideration for improving resource utilization in the biorefinery. The fermentation inhibitors generated during biomass pretreatment and conversion accumulate in the process stream if the water is recycled without treatment. Presence of sugar- and lignin- degradation products such as furfural, vanillic acid and 4-hydroxybenzaldehyde has been shown to drop fermentation yields precipitously. In this work, we demonstrate the potential for electricity and hydrogen production from these compounds using microbial fuel cells and electrolysis cells. Estimates for bioenergy production via such systems in full-scale biorefineries will also be presented. Production of hydrogen as an alternate product can have a profound impact on the biorefinery process efficiency and economics. Challenges to implement this in the biorefinery including scale up of these systems will be addressed. [Oral presentation]