Cells of this strain increase the intensity of red color produced proportionally to the concentration of copper ions in
incubation medium,allowing the detection of copper ions in the range of 1–100 μM. The system was optimized for the use of tester strain cells immobilized in alginate beads and static incubation in the presence of various copper ion concentrations under conditions of low aeration.The final coloration of the beads develops quickly (in 3060 min) after the beads are exposed to aerial oxygen.