The air pollution due to various gases, especially carbon dioxide (CO2), has contributed to climate change, and the crucial factor will be reducing CO2 emission as well as conversion of CO2 in valuable products for clean future. The microbial electrosynthesis (MES) is a promising approach for reduction of CO2 by biological pathway utilizing the metabolic capacity of microorganisms to transform CO2 into various valuable products such as methane, butyrate, n-caproate, isobutyric acid, propionic acid, acetate, hydrogen, hydrogen peroxide, formate, ethanol, and butanol. This chapter explores the fundamentals of MES focusing on its ability to produce valuable products using microbial metabolic activity as well as impact of the microbial community on the product generation. The pathways and mechanism by which the electroactive microbes convert chemical energy of molecules to electrical energy are discussed in detail. The chapter also examines the influence of various operational parameters of MES such as microbial diversity, substrate type, membrane, electrodes, and operating conditions on the efficiency of MES. The recent advancements in MES technology and its capability to reduce CO2 can be a potential solution for carbon capture for circular bioeconomy. The integration of MES with other technologies can be a framework to mitigate the climate change due to excessive CO2 emission and produce value aided chemicals to meet the demand of sustainable future.