Sustainable vision toward development of microbial electrosynthesis for diverse resource recovery: Circular economy

Carbon emissions and demand for industrial chemicals have forced us to synthesize valuable resources from CO2 sequestration through bioelectrochemical pathways. Microbial electrosynthesis system (MES) can recover valuable resources, including acids, alcohols, gases, and industrial byproducts from CO2 by mimicking the artificial photosynthesis process. Currently, MES is still in the proof-of-concept stage; however, targeting the synthesis of high yields of expensive chemicals can benefit the circular economy and sustainable development. For MES upgradation, demanding resources other than fatty acids need to be promoted along with market statistics to sustain in the global competition. From economic consideration, carbon monoxide (CO), oxalic and formic acid, hydrogen gas (H-2), propanol, and acetaldehyde are the most economically viable and competitive byproducts during CO2 reduction in MES. The present review focused on MES's sustainable outlook, governing parameters, and techno-economic feasibility by targeting upscaling trials and downstream processing. The strength, weakness, opportunities, and threats analysis represents that a two-stage process can be helpful to improve the yield and purity of resources recovered while considering the economics of an integrated process. It can be seen that using the mixed culture with specific bacteria enrichment, employing a continuous operation/integrated system, optimizing electrode material, and boosting the electron transfer route are the most favourable methods to enhance MES's performance and market value. The prediction by mathematical and modeling system applications, or high-valued molecule production and simpler downstream processing are the MES's prioritized considering in techno-economic aspect in the future.