Cells of this strain increase the intensity of red color produced proportionally to the concentration of copper ions in
incubation medium,allowing the detection ofcopper ions in the range of1–100 μM. The system was optimized for the use of tester strain cells immobilized in alginate beads and static in cubation in the presence of various copper ion concentrations under conditions of low aeration.The final coloration of the beads develops quickly (in3060min) after the beads are exposed to aerial oxygen.