LAUSR

Abstract Microbial electrosynthesis (MES) is an innovative technology, which can yield valuable organic chemicals with concomitant CO 2 sequestration by employing microbes as biocatalysts. The mode of operation has an imperative role in the performance of MES, thus, affecting the yield of synthesized organic chemicals from the MES. However, to the best of our knowledge, the optimal mode of operation for MES has not been determined till date. Hence, in the present investigation, two MES were operated: one in batch mode (MES-B) and another in continuous mode (MES-C), and their performance was monitored. The MES-B exhibited 31%, 33.5% and 44% higher production rate of acetate, propionate and butyrate, respectively, in comparison to MES-C. Moreover, the performance of MES-B also stabilized faster, and microbiome in the cathodic chamber of MES-B was able to accept 26% more electrons supplied to it externally, which were employed as reducing equivalents to reduce CO 2 . The enactment of MES-B was superior to that of MES-C due to the higher retention of CO 2 and hydrogen in cathodic chamber of MES-B. Therefore, operating MES in batch mode would aid in yielding more organic chemicals through CO 2 sequestration. Graphic abstract