Real-time microbial growth monitoring by combining microbial fuel cell-based device with modified Nernst equation

In this work, we demonstrate a novel design that integrates a modified Nernst equation and readings from a microbial fuel cell (MFC)-based device, facilitating real-time monitoring of microbial growth. The MFC-based device is comprised of an H-shaped double-chamber MFC, specifically designed to incorporate an oxidation-reduction potential (ORP) sensor, allowing for simultaneous measurements of both parameters. The Nernst equation was adjusted to assimilate readings from both the ORP sensor and the MFC device, ultimately deriving a unitless curve that represents the online dynamics of microbial growth. This curve exhibits two distinct peaks: the first peak indicates the initiation of the exponential phase, while the second peak signals its termination. The proposed design can be seamlessly integrated into fermentation processes to continually monitor progress, boost productivity, develop tailored control strategies that meet specific objectives, and so on.