Research review paperBioelectrohydrogenesis and inhibition of methanogenic activity in microbial electrolysis cells - A review

•Comprehensive review of bioelectrohydrogenesis in microbial electrolysis cell (MEC)•Factors that influence hydrogen production kinetics in MECs are discussed.•Approaches for inhibiting methanogenic activity in MECs are discussed in detail.•Effective suppression of methanogenesis in MEC is challenging and requires future research.

Microbial electrolysis cells (MECs) are a promising technology for biological hydrogen production. Compared to abiotic water electrolysis, a much lower electrical voltage (~ 0.2 V) is required for hydrogen production in MECs. It is also an attractive waste treatment technology as a variety of biodegradable substances can be used as the process feedstock. Underpinning this technology is a recently discovered bioelectrochemical pathway known as “bioelectrohydrogenesis”. However, little is known about the mechanism of this pathway, and numerous hurdles are yet to be addressed to maximize hydrogen yield and purity. Here, we review various aspects including reactor configurations, microorganisms, substrates, electrode materials, and inhibitors of methanogenesis in order to improve hydrogen generation in MECs.