A Soil Bioelectrochemical Platform for Monitoring Electrochemically Active Biofilm Development

We developed a low-cost, portable four-channel potentiostat for simultaneous electrochemical measurements in soil. The instrument supports open-circuit potential monitoring, cyclic voltammetry, and chronoamperometry, with a programmable potential range of ±4.096 V and current-measurement configurations for large-area electrodes and microelectrodes. It operates on USB power or a Li-ion battery and includes onboard data storage and Bluetooth communication. Benchmarking against a commercial potentiostat in individual three-electrode cells showed comparable voltammetric responses under the tested conditions. We also evaluated simultaneous operation using shared reference and counter electrodes. In 40-d soil experiments, the instrument recorded current responses from carbon fabric electrodes polarized at different potentials and carbon-tipped microelectrodes positioned at different depths. These measurements demonstrated temporal variation and differences among electrode potentials and depths, including nanoampere-scale responses from microelectrodes. The results establish the instrument’s capability for simultaneous multielectrode soil measurements and for monitoring biofilm activity.