Anaerobic toluene degradation by Cupriavidus metallidurans CH34 in Bioelectrochemical Systems

Bioelectrochemistry is a technology based on the connection between microbes (named as exoelectrogens) and electrodes. A promising field of application is the bioelectrochemical remediation, an effective strategy in environments where the absence of suitable electron acceptors limits classic bioremediation. Bioelectrochemical remediation of hydrocarbons with pure strains and microbial communities has been reported. However, only few exoelectrogenic hydrocarbonoclastic bacteria have been characterized so far and most researches have primarily focused on testing the hydrocarbonoclastic capacities of already known exoelectrogenic strains. In this study we took a different approach, and we aimed at studying the exoelectrogenic activity of Cupriavidus metallidurans CH34, a model metal-resistant strain, whose hydrocarbonoclastic capacities have been already reported. The capacity to degrade toluene under anaerobic conditions and the exoelectrogenic capacity of Cupriavidus metallidurans CH34 was determined. We demonstrated for the first time that strain CH34 is able to degrade toluene under denitrifying conditions and the removal of this pollutant in MEC was assessed. Toluene degradation was linked to current production, showing current peaks after every toluene respike (maximum current density 48 mA/m2 ).