Anaerobic digestion and microbial electrolysis cells: methane production from effluents of the ABE fermentation of vine shoots

Carrillo‑Peña D, Escapa A, Hijosa‑Valsero M, Paniagua‑García AI, Díez‑Antolínez R, Mateos R (2022) Bioelectrochemical enhancement of methane production from exhausted vine shoot fermentation broth by integration of MEC with anaerobic digestion. Biomass Conversion and Biorefinery. https://doi.org/10.1007/s13399-022-02890-7.

Abstract: A microbial electrolysis cell integrated in an anaerobic digestion system (MEC-AD) is an efficient configuration to produce methane from an exhausted vine shoot fermentation broth (EVS). The cell worked in a single-chamber two-electrode configuration at an applied potential of 1 V with a feeding ratio of 30/70 (30% EVS to 70% synthetic medium). In addition, an identical cell operated in an open circuit was used as a control reactor. Experimental results showed similar behavior in terms of carbon removal (70–76%), while the specific averaged methane production from cycle 7 was more stable and higher in the connected cell (MECAD) compared with the unpolarized one (OCAD) accounting for 403.7 ± 33.6 L CH4·kg VS−1 and 121.3 ± 49.7 L CH4·kg VS−1, respectively. In addition, electrochemical impedance spectroscopy revealed that the electrical capacitance of the bioanode in MECAD was twice the capacitance shown by OCAD. The bacterial community in both cells was similar but a clear adaptation of Methanosarcina Archaea was exhibited in MECAD, which could explain the increased yields in CH4 production. In summary, the results reported here confirm the advantages of integrating MEC-AD for the treatment of real organic liquid waste instead of traditional AD treatment.

Link to journal article (open access): https://doi.org/10.1007/s13399-022-02890-7.

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