Potentiostatic enrichment of electrochemically active bacteria from sediments and soils

The majority of studies on electrochemically active mixed microbial consortia investigate domestic wastewater. While this is relevant for industrial applications such as microbial fuel cells (MFCs), it is likely that only a... [ view full abstract ]

The majority of studies on electrochemically active mixed microbial consortia investigate domestic wastewater. While this is relevant for industrial applications such as microbial fuel cells (MFCs), it is likely that only a small fraction of electrochemically active microorganisms is found in domestic wastewater. Because of the abundance of microbial consortia in soils and sediments, combined with higher insoluble metal and mineral concentrations which can be used as external electron acceptors, soils and sediments are likely to host a much larger diversity of electrochemically active bacteria . There is also potential to discover novel microorganisms capable of Extracellular Electron Transfer (EET) mechanisms with relevant application to biogeochemistry, biosensors and bioremediation. In this study, we will investigate the potentiostatic enrichment and preliminary characterization of electrochemically active microorganisms from contaminated soils and sediments.

Soils and sediments from polluted and pristine sites will be used as inoculum for enrichment of electrochemically active bacteria, enriched by growth on carbon felt working electrodes poised at 0.2 V vs Ag/AgCl in 120 mL stirred anaerobic reactors at 30°C. Carbon felt was selected because of its large accessible surface area for biofilm formation. The microbial composition of the sediment inoculum and the enriched biofilm will be determined by metagenomic analysis. The biofilm’s electrochemical properties will be measured by voltamperometric methods and electrochemical impedance spectroscopy.