Biofilm Driven Electrode Optimization in Bioelectrochemical Systems

Abstract

The transition toward sustainable ammonia synthesis is critical in reducing the environmental footprint of the fertilizer industry, traditionally dominated by the energy-intensive Haber-Bosch process. Bioelectrochemical systems (BES) offer a promising green alternative by leveraging electroactive microorganisms for ammonia production via bioelectrochemical nitrogen fixation (e-BNF). A central challenge in BES performance lies in optimizing the biofilm–electrode interface, where microbial activity and electron transfer converge. This thesis investigates the interplay between carbon-based electrode materials and electroactive biofilm development using a proprietary strain (Centeobacter sp. CTN001) under controlled anaerobic conditions. Chronoamperometry and cyclic voltammetry were employed to evaluate electrochemical activity, while protein content, dry biomass, and CFU counts were quantified to assess biofilm maturity. Surface treatment (e.g., acid activation) and functionalization strategies (e.g., carbon-black inks and alginate composites) were applied to enhance electrode biocompatibility and conductivity. Findings reveal that surface morphology and chemical modification significantly influence early biofilm formation and long-term current generation. Among the tested materials, carbon felt exhibited the highest current density, while ELAT carbon cloth showed comparable performance with superior handling properties and greater suitability for further functionalization. These results contribute valuable insight into material-biological interactions and inform the rational design of BES anodes for decentralized, sustainable ammonia production.