Real-Time Detection of Mercury in Water with a Bacterial Bioluminescent Silicon Photomultiplier System

This study presents a compact and highly sensitive optoelectronic biosensing system that integrates genetically engineered Escherichia coli bacteria with a Silicon Photomultiplier-based detection module for monitoring mercury in aquatic environments. The engineered bacteria produce bioluminescent signals in response to mercury exposure, with light intensity directly proportional to the concentration of bioavailable metal ions. By combining the high photon detection efficiency and low-noise performance of Silicon Photomultipliers with a custom-built acquisition interface, our system enables real-time monitoring of pollutants at trace levels. Additionally, the multi-chamber configuration supports simultaneous measurements under different conditions, facilitating direct biosensor calibration and enhancing the reliability of statistical analysis. Measurements demonstrate a Limit of Detection of 0.12 μg/L, eight times below current environmental regulatory thresholds, and a dynamic range spanning about two orders of magnitude. Compared to a conventional laboratory-grade luminometer, our system achieves equivalent sensitivity while offering significant advantages in terms of portability, cost, and remote control. These features highlight its strong potential for environmental monitoring and risk assessment.