Effect of humic acids on electricity generation integrated with xylose degradation in microbial fuel cells

Abstract

Pentose and humic acids (HA) are the main components of hydrolysates, the liquid fraction produced during thermohydrolysis of lignocellulosic material. Electricity generation integrated with xylose (typical pentose) degradation as well as the effect of HA on electricity production in microbial fuel cells (MFCs) was examined. Without HA addition the maximum power density increased from 39.5 mW/m(2) to 83 mW/m(2) when initial xylose concentrations increased from 1.5 to 30 mM, while coulombic efficiency ranged from 13.5% to 52.4% for xylose concentrations of 15 and 0.5 mM, respectively. Compared to controls where HAs were not added, addition of commercial HA resulted in increase of power density and coulombic efficiency, which ranged from 7.5% to 67.4% and 24% to 92.6%, respectively. Digested manure wastewater (DMW) was tested as potential mediator for power generation due to its content of natural HA, and although it could produce higher coulombic efficiency namely 32.2% than the control of 18.3%, showed lower power density which was approx. 57 mW/m(2) in comparison to power density of the control which was 69 mW/m(2). Presence of commercial HA or DMW in the anode chamber resulted in faster xylose degradation and formation of more oxidized products (acetate and formate) as well as less reduced products (lactate and ethanol) compared to the controls. The reduced power generation in the presence of DMW was attributed to the presence of bacterial inhibitors such as phenolic compounds. Therefore, new feedstocks for MFCs, containing both mediators and substrates, such as lignocellulose hydrolysates should be considered for their applicability in MFCs.

Evaluation of electricity production from alkaline pretreated sludge using two-chamber microbial fuel cell

“…Comparing the changes in three-dimensional fluorescence spectra and electricity production, it could be found that the change in humic-like substances showed a positive correlation with the electricity production of the MFC. The results for the humic-like substances are similar to those of Thygesen et al [40] and Huang and Angelidaki [41], who found that humic acid could enhance the electricity production of MFC because it could act as mediator.…”

Performance improvement of whey-driven microbial fuel cells by acclimation of indigenous anodophilic microbes

“…The power density generated by the devices was calculated by Pd=VI/A; where, V is the voltage; I is the current and A is the anode surface area (Huang and Angelidaki, 2008a). Both efficiency of electron transfer to the anode surface (coulombic efficiency (εcb)) and substrate degradation rate (SDR) were calculated as explained by Huang and Angelidaki (2008b), Mohan et al (2008) and Antonopoulou et al (2010).…”

Generation of Electricity and Analysis of Microbial Communities in Wheat Straw Biomass-Powered Microbial Fuel Cells

“…Chemical and biological approaches to sustainable energy production from the liquefied hydrolysates to energy carriers, such as methane, ethanol, and H 2 , have been developed. However, many of these approaches encounter technical and economical hurdles (10,12,15,16). An alternative strategy is direct conversion of wheat straw biomass to electrical energy in microbial fuel cells (MFCs).…”

“…MFCs are bioelectrochemical reactors in which microorganisms mediate the direct conversion of chemical energy stored in organic matter or bulk biomass into electrical energy (12,15,16,40). Various substrates, such as simple carbohydrates, lowmolecular-weight organic acids, starch, amino acids, chitin, cellulose, domestic wastewater, food-processing wastewater, recycled paper wastewater, and marine sediment organic matter, have been successfully utilized for power generation in MFCs (16-18, 27, 30, 33).…”