Chapter 10 - Methanogen-electrode/conductive material interactions for methane production from carbon dioxide

Abstract

Methanogen-electrode/conductive material interactions for renewable biogas and biomethane production from carbon dioxide (CO2) are the key component governing the operations of anaerobic digestion (AD) and microbial electrochemical technologies (METs). However, to optimize methanogenic activities in AD and MET, an understanding of interactions between methanogens and conductive materials/electrodes is required. First, the fundamentals of methanogenesis and electromethanogenesis processes in AD and MET and their electron transfer pathways, such as direct electron transfer, indirect electron transfer, and direct interspecies electron transfer, are discussed. Moreover, we critically examine and scrutinize how different conductive materials, types of anodes and biocathodes, and various operating parameters such as organic loading rates, the food-to-microorganisms ratio, temperatures, mixing, applied energy levels, pH, reactor configurations, inoculum sources, and microbial communities can be engineered to optimize methanogenesis and electromethanogenesis in AD and MET. This chapter provides an overview of different fundamental and applied aspects of interactions between methanogens and conductive materials/electrodes in AD and METs in terms of CO2 use and methane recovery.