Microbial electrosynthesis represents a promising approach for renewable energy storage in which chemically stable compounds are produced using CO2 as feedstock. This report aims the continuous production of acetate through microbial electrosynthesis from CO2 and assesses how the production rates could be increased.
A continuous acetate production rate of 0.98 mmol C·LNCC−1·d−1 was obtained using CO2 as feedstock and with a pH control around 5.8. This conditions increased substrate availability and favoured microbial electrosynthesis. Cyclic voltammograms demonstrated the electroautotrophic activity on the biocathode surface, which increased due to the pH control and caused current demand and acetate production rate to exponentially rise up.
The pH decrease was shown as an effective strategy to increase substrate availability and enhance microbial electrosynthesis. By making microbial electrosynthesis a feasible technology, CO2 could become an alternative feedstock for the carboxylate platform.