Characterization of Anaerobic Biofilms Growing on Carbon Felt Bioanodes Exposed to Air

• Main Authors: Raúl M. Alonso, Guillermo Pelaz, María Isabel San-Martín, Antonio Morán, Adrián Escapa
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Catalysts
• Subjects: exoelectrogen; biocatalyst; microenvironment; porous electrode; anaerobic
• Online Access: https://www.mdpi.com/2073-4344/10/11/1341

The role of oxygen in anodic biofilms is still a matter of debate. In this study, we tried to elucidate the structure and performance of an electrogenic biofilm that develops on air-exposed, carbon felt electrodes, commonly used in bioelectrochemical systems. By simultaneously recording the current density produced by the bioanode and dissolved oxygen concentration, both inside and in the vicinity of the biofilm, it was possible to demonstrate the influence of a protective aerobic layer present in the biofilm (mainly formed by <i>Pseudomonas</i> genus bacteria) that prevents electrogenic bacteria (such as <i>Geobacter</i> sp.) from hazardous exposure to oxygen during its normal operation. Once this protective barrier was deactivated for a long period of time, the catalytic capacity of the biofilm was severely affected. In addition, our results highlighted the importance of the material’s porous structure for oxygen penetration in the electrode.