Microbial Electrolysis Cells in Biohydrogen Production

Microbial electrolysis cell (MEC) has been regarded as a promising technology to produce hydrogen using electrochemically active bacteria. The yield of hydrogen can be up to three times higher compared to simple microbial fermentation. A hydrogen yield of 12 mol/mol hexose is theoretically reached compared to 4 mol/mol using dark fermentation. In addition to the large theoretical yield of biohydrogen, MECs demand lower energy for electrohydrogen reactions. This chapter overviews MEC technology basics and critical factors affecting its performance for hydrogen production, such as reactor design, electrode materials, microorganisms, and substrates. Technoeconomic aspects of different methods to produce hydrogen are presented and compared to MECs.