Bioelectrochemical Systems for Electricity and Hydrogen Production in Biorefinery

Abstract

Production of renewable electricity and hydrogen in biorefinery can add a significant value towards development of a sustainable bioeconomy for the 21st century. Here, we investigate bioelectrochemical systems for conversion of biomass and waste using biological fuel cells and electrolysis cells. The ability to extract electrons from biomass components efficiently can lead to novel pathways for production of energy, fuels and chemicals. Understanding the electron transfer and charge transfer issues is critical in developing functional bioelectrochemical cells. Current production from two biomass-derived streams was investigated determining Coulombic efficiency, cathode efficiency and electrical efficiency. The effect of substrate concentration and loading on performance was studied to understand kinetic vs. mass transfer issues. In addition to the electrochemical aspects, bioconversion aspects become critically important for valorizing complex streams such as bio-derived liquids. In addition to sugars, transformation of furanic and phenolic compounds derived from lignin and hemicellulose is important, since they are rich source of electrons. Removal of furfural, HMF, phenolic acids and acetic acid was demonstrated and conversion efficiencies were calculated. Improvements in current density and coulombic efficiency of the bioanode were studied by varying multiple operational parameters. The electron transfer process was measured against the proton and charge transfer steps to identify mechanistic factors controlling the conversion of the complex substrates to electricity and hydrogen.