Hydrogen and Methane generation from Biowaste: Enhancement and Upgrading via Bioelectrochemical Systems

Bioelectrochemical systems (BESs) are emerging technologies that are based on catalyzing (bio-)anode and (bio-)cathode reactions from waste biomass by exoelectrogenic microorganisms. Microbial electrolysis cell (MEC), which is one of the BESs’ technologies, is typically used to degrade organic wastes or wastewater for bioenergy recovery and biosynthesis. As one of the promising biotechnologies for resource recovery, value-added products have been obtained by MEC- or ME-integrated systems, such as hydrogen, methane, ethanol, etc. The fundamental reactions of (bio-)electron transport through anodic oxidation are well understood and allow us to increase reactor performance and efficiency. More attentions have been recently paid to cathode reactions on proton/electron transport and recovery, with or without microbial activities. Biogas upgrading systems have also been promoted in integrated systems, by combining bioelectrochemistry with various anaerobic processes. This chapter will focus on energy gas generation from waste organics involved in bioelectrochemical pathways and give an overview of bottlenecks and challenges related to this technology.