Role of applied potential on microbial electrosynthesis of organic compounds through carbon dioxide sequestration

Microbial electrosynthesis (MES) is a novel technology that can be used to sequester carbon and simultaneously produce organic compounds by the application of electricity in the presence of biocatalysts. This investigation was aimed at determining the ideal imposed potential required to synthesize organic compounds from the CO2 present in biogas. Different potentials namely from - 0.6 V to - 1.0 V vs standard hydrogen electrode (SHE), were applied and effect on performance of MES was evaluated. The coulombic efficiency, carbon recovery efficiency and yield of organic compounds was found to be positively affected by the cathodic imposed potential. The yield of acetate and butyrate was enhanced by 1.67 and 1.61 times, respectively, when the cathodic imposed potential was changed from - 0.6 V to - 1.0 V vs SHE. However, with increase in the applied potential, the operating cost of MES increases due to the cost of electricity. Thus, energy requirement was estimated to determine the amount of energy consumed for synthesizing unit mole of the product. Depending on this factor, MES with applied potential of- 0.7 V vs SHE was found to be optimum for the production of organic compounds from CO2 with the least energy requirement of 9.15 Wh mol(-1).