Tamás Rózsenberszki

Microbial electrohydrogenesis linked to dark fermentation as integrated application for enhanced biohydrogen production: A review on process characteristics, experiences and lessons

Microbial electrohydrogenesis cells (MECs) are devices that have attracted significant attention from the scientific community to generate hydrogen gas electrochemically with the aid of exoelectrogen microorganisms. It has been demonstrated that MECs are capable to deal with the residual organic materials present in effluents generated along with dark fermentative hydrogen bioproduction (DF). Consequently, MECs stand as attractive post-treatment units to enhance the global H2 yield as a part of a two-stage, integrated application (DF-MEC). In this review article, it is aimed (i) to assess results communicated in the relevant literature on cascade DF-MEC systems, (ii) describe the characteristics of each steps involved and (iii) discuss the experiences as well as the lessons in order to facilitate knowledge transfer and help the interested readers with the construction of more efficient coupled set-ups, leading eventually to the improvement of overall biohydrogen evolution performances.

Development of bioelectrochemical systems using various biogas fermenter effluents as inocula and municipal waste liquor as adapting substrate

The purpose of this research was to improve microbial fuel cell (MFC) performance - treating landfill-derived waste liquor - by applying effluents of various biogas fermenters as inocula. It turned out that the differences of initial microbial community profiles notably influenced the efficiency of MFCs. In fact, the adaptation time (during 3 weeks of operation) has varied significantly, depending on the source of inoculum and accordingly, the obtainable cumulative energy yields were also greatly affected (65% enhancement in case of municipal wastewater sludge inoculum compared to sugar factory waste sludge inoculum). Hence, it could be concluded that the capacity of MFCs to utilize the complex feedstock was heavily dependent on biological factors such as the origin/history of inoculum, the microbial composition as well as proper acclimation period. Therefore, these parameters should be of primary concerns for adequate process design to efficiently generate electricity with microbial fuel cells.