Details

Autor(en) / Beteiligte

• Sandfeld, Tobias
• Grøn, Louise Vinther
• Munoz, Laura
• Meyer, Rikke Louise
• Koren, Klaus
• Philips, Jo

Titel

Considerations on the use of microsensors to profile dissolved H.sub.2 concentrations in microbial electrochemical reactors

Ist Teil von

• PloS one, 2024-01, Vol.19 (1), p.e0293734

Ort / Verlag

Public Library of Science

Erscheinungsjahr

2024

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Measuring the distribution and dynamics of H.sub.2 in microbial electrochemical reactors is valuable to gain insights into the processes behind novel bioelectrochemical technologies, such as microbial electrosynthesis. Here, a microsensor method to measure and profile dissolved H.sub.2 concentrations in standard H-cell reactors is described. Graphite cathodes were oriented horizontally to enable the use of a motorized microprofiling system and a stereomicroscope was used to place the H.sub.2 microsensor precisely on the cathode surface. Profiling was performed towards the gas-liquid interface, while preserving the electric connections and flushing the headspace (to maintain anoxic conditions) and under strict temperature control (to overcome the temperature sensitivity of the microsensors). This method was tested by profiling six reactors, with and without inoculation of the acetogen Sporomusa ovata, at three different time points. H.sub.2 accumulated over time in the abiotic controls, while S. ovata maintained low H.sub.2 concentrations throughout the liquid phase (< 4 [mu]M) during the whole experimental period. These results demonstrate that this setup generated insightful H.sub.2 profiles. However, various limitations of this microsensor method were identified, as headspace flushing lowered the dissolved H.sub.2 concentrations over time. Moreover, microsensors can likely not accurately measure H.sub.2 in the immediate vicinity of the solid cathode, because the solids cathode surface obstructs H.sub.2 diffusion into the microsensor. Finally, the reactors had to be discarded after microsensor profiling. Interested users should bear these considerations in mind when applying microsensors to characterize microbial electrochemical reactors.