Microbial Electrosynthesis for Producing Medium Chain Fatty Acids

Microbial electrosynthesis (MES) employs microbial catalysts and electrochemistry to enhance CO₂ bioconversion to organics with concurrent waste biorefining capability. The aim of this review is to comprehensively discuss the current state of the art and prospects of medium chain fatty acids (MCFAs) production in MES from CO₂ and organic wastes. Fundamental mechanisms and development of MCFAs production via conventional fermentation are introduced as well. Studies on MCFAs production in MES are summarized, highlighting the strategy of multiple-electron donors (EDs). Challenges for MCFAs production in MES from CO₂ are presented, and the primary discussions included methanogenesis inhibition, adenosine triphosphate (ATP) limitations of acetogens, and production of limited EDs via solventogenesis. Possible applications of electrochemical approaches to promote the bioconversion of actual waste materials with MCFAs production are analyzed. Finally, future directions are explored, including multi-stage reactions, substrate supply, product extraction, and microbial pathways.