Effects of low electric current (LEC) treatment on pure bacterial cultures

This research focused on the effects of low electric current (LEC) on the cell viability and metabolic activity of Escherichia coli and Bacillus cereus. Different LEC intensities at fixed amperage were applied, employing either graphite or copper electrode pairs, and the effects were determined by conventional cultural methods and bioindicators. On E. coli, the LEC with graphite electrodes at 5 and 10 mA led to no significant variation, but at 20 and 40 mA there was increasing inhibition of both the enzymatic activities and growth, and a reduction in ATP content. On B. cereus, similar experiments at the lower amperages did not have any inhibitor effects, however, the 40 mA current stimulated growth, ATP content and some enzymatic activities. The LEC treatment using copper electrodes caused, already at 5 mA, inhibition of bacterial growth and metabolic and enzymatic activities in both E. coli and B. cereus. On the basis of the obtained results using different amperages and electrodes, we can conclude that E. coli seem to be more sensitive compared with B. cereus. The study increases the knowledge on LEC treatment effects on the pure bacterial cultures.