Biofuel Production from Bioelectrochemical Systems

Abstract

Bioelectrochemical systems, including microbial fuel cells (MFCs), microbial electrolysis cells (MECs), and microbial electrosynthesis cells, are promising technologies for dealing with water pollution and the energy crisis. In these systems, electrochemically active bacteria attached on electrodes can degrade organic matter in wastewater while producing electricity, gas fuels, and other value-added chemicals. In this chapter, we review the current progress of MECs and microbial electrosynthesis cells, which are used to produce hydrogen and value-added chemicals (such as acetate, hydrogen peroxide, ethanol, and formic acid). However, the production of liquid value-added chemicals is still in its infancy, and there are many challenges to its application, such as low production rates, high internal resistance, and expensive electrode materials. Compared with liquid fuels, gaseous biofuels (e.g., hydrogen and methane) are much easier to separate and need less energy for further purification. Therefore, we mainly focus on H2 production from MECs and methane production from microbial electrosynthesis cells. This chapter reviews recent development of new electrode materials, configurations, electron transfer manners, microbial ecosystems, and applications for the two devices to promote a general understanding and identify future research directions for bioelectrochemical systems.