Sulfate biosensor for environmental applications

Abstract Sulfate is present in all freshwater and marine environments reduced to toxic corrosive hydrogen sulfide by anaerobic bacteria. By measuring depth profiles of sulfate sediments, it possible obtain estimates reduction rates (SRRs). A whole‐cell microscale biosensor for was constructed placing a mixture sulfate‐reducing aerobic bacteria front microsensor. The were supplied with electron donors from reservoir behind the bacterial biomass. ensured conditions deeper parts 150‐ μ m‐thick layer, so that reducers could be active. typical tip diameter 50 m. calibration curve close linear 0–2 mM range, detection limit about 10 M. 90% response time varied between 90 220 s, slowest at low concentrations. Oxygen ferrous iron environmental concentrations gave no interference, but there 6% signal difference stirred stagnant liquid medium. sensitivity modulated applying charge sensor interior an external electrode. lifetime usually few weeks. used measure sediment.