Spent Tea Leaves and Coffee Grounds as Potential Biocathode for Improved Microbial Electrosynthesis Performance

Microbial electrosynthesis (MES) has emerged as a sustainable energy platform capable of simultaneous wastewater treatment and valuable chemical production. The performance MES, like other bioelectrochemical systems, largely depends on its electrode (cathode), providing the for microbial growth well electron transfer. However, most electrodes are expensive, their nonrenewable characteristics, cost, poisoning nature major bottlenecks in MES commercialization. Thus, several efforts have been made to explore potential waste carbon-based reduce carbon footprints manufacturing costs. In this study, feasibility using spent tea leaves (STL) coffee grounds (SCG) biocathode was tested. Different tests suggested improved with STL SCG along reduced resistance current density. A 1.5- 2.0-fold increase cyclic voltammetry (CV) output observed STL, respectively, substantial mediator peaks high intensity indicating enhanced electrocatalytic activity. Enrichment some fermentative exoelectrogenic classes such Clostridia, Bacteroidia, Deltaproteobacteria led 1.3- 1.4-fold butyrate production cathode, respectively. These results demonstrate cathode