Design and operation of pilot-scale microbial electrosynthesis for the production of acetic acid from biogas with economic and environmental assessment.

The embryonic technology of microbial electrosynthesis (MES) possesses the potential to alleviate global CO concentration with concomitant recovery of valuables. However, due to the significant bottlenecks of inferior yield of valuables and higher capital cost, its potential has not been fully realized at a larger scale till date. With the aim of bridging this lacuna, a first of its kind pilot-scale MES (PSMES) was designed and operated to yield acetic acid from biogas. The PSMES was able to produce 70.55 g m.day of acetic acid in its extraction chamber with the coulombic efficiency of 77.8 % for an imposed cathode potential of -1.0 V vs. standard hydrogen electrode. Moreover, life cycle assessment (LCA) and economic analysis of the PSMES was also conducted to elucidate the economic and environmental feasibility of the same. From the LCA and economic analysis of the PSMES, it was inferred that acrylic sheet and carbon felt used during the fabrication of PSMES were the major culprit in terms of both environmental and economic sustainability and thus should be replaced with greener but cost-effective materials. Therefore, these results would guide the budding scholars in designing more economical and environment friendly scaled-up MES, thus paving towards the commercialization of this ingenious technology.