Electrotrophy of biocathodes regulates microbial-electro-catalyzation of CO2 to fatty acids in single chambered system.

Microbial electrochemical conversion of CO2 to value-added products needs effectual biocathodes. In this study, three different working electrodes (biocathode) namely carbon cloth (CC, MES1), stainless steel mesh (SS, MES2) and hybrid electrode (CC + SS, MES3) were evaluated in membrane-less single-chambered Microbial electrosynthesis systems (MESs). Performance of MES was assessed by total volatile fatty acids (VFA) productivity and, reductive current generations upon continuous poised potential (-0.4 V vs. Ag/AgCl (3.5 M KCl)). MES3 showed higher VFA synthesis (CC + SS; 1.4 g VFA/L), followed by MES1 (CC; 1.1 g VFA/L) and MES2 (SS; 0.8 g VFA/L) with corresponding reductive current generation of -1.13 mA, -2.74 mA and -0.39 mA. Electro-kinetics revealed the biocathode efficacy towards enhanced electrotrophy with confined electron losses by regulating electron flux in the system. The study infers the potential of hybrid electrode as an efficient biocathode for the reduction of CO2 to VFA synthesis.