Abstract
Microbial electrosynthesis (MES) is a process where bacteria acquire electrons from a cathode to convert CO2 into multicarbon compounds or methane. In MES with Sporomusa ovata as the microbial catalyst, cathode potential has often been used as a benchmark to determine whether electron uptake is hydrogen-dependent. In this study, H-2 was detected by a microsensor in proximity to the cathode. With a sterile fresh medium, H-2 was produced at a potential of -700 mV versus Ag/AgCl, whereas H-2 was detected at -500 mV versus Ag/AgCl with cell-free spent medium from a S. ovata culture. Furthermore, H-2 evolution rates were increased with potentials lower than -500 mV in the presence of cell-free spent medium in the cathode chamber. Nickel and cobalt were detected at the cathode surface after exposure to the spent medium, suggesting a possible participation of these catalytic metals in the observed faster hydrogen evolution. The results presented here show that S. ovata-induced alterations of the cathodic electrolytes of a MES reactor reduced the electrical energy required for hydrogen evolution. These observations also indicated that, even at higher cathode potentials, at least a part of the electrons coming from the electrode are transferred to S. ovata via H-2 during MES.
Original language | English |
---|---|
Article number | 166 |
Journal | Catalysts |
Volume | 9 |
Issue number | 2 |
ISSN | 2073-4344 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- industrial biotechnology
- electrochemistry
- biohydrogen
- biocatalysis
- process development
- bacteria