Electrochemical determination of cell populations

Determination of cell populations was carried out using the potentiostatic systems. The system was constructed from two platinum electrodes and a saturated calomel electrode. The anode of a reference system was covered with cellulose dialysis membrane. The response time of the system was 3-5 min, and current differences between the two components were proportional to cell populations in a culture of Bacillus subtilis. Current differences were reproducible with an average relative error of 4%. Cell populations of B. subtilis in a fermentor could be continuously determined by using this new electrochemical method. Moreover, these systems can be sterilized by heat before use.