Microbial bioanodes with high salinity tolerance for microbial fuel cells and microbial electrolysis cells

• Microbial bioanodes were formed on carbon felt under constant applied potential.
• Acetate was supplemented to avoid any significant current decrease.
• Sediments from salt marsh were used as inoculum.
• Current densities up to 85 A·m− 2 were reached.
• The bioanodes operated in 45 g·L NaCl solution (1.5 times seawater salinity).

Increasing the conductivity of the electrolytes used in microbial electrochemical systems is an essential prerequisite to the large-scale success of these technologies. Microbial bioanodes formed from a salt marsh inoculum under constant acetate feeding generated up to 85 A·m− 2 in media containing 776 mM NaCl (45 g·L− 1, 1.5 times the salinity of seawater). These values were the highest salinities accepted by a microbial anode so far and the highest current densities reported with felt graphite electrodes.