TiO₂-coated electrodes for pulsed electric field treatment of microorganisms

Pulsed electric fields (PEF) can cause irreversible damage to bio-membranes and may result in inactivation of microorganisms. The aim of this paper is to investigate the PEF treatment of the yeast Saccharomyces cerevisiae, using a novel treatment cell with parallel-plane electrodes coated with a 2 µm thin TiO2 film. Two different PEF waveforms, square and exponential, with magnitudes of 67 kV/cm and 80 kV/cm, were used in this study. The efficacy of the PEF treatment was assessed by comparison of the surviving treated and untreated yeast populations, and it was shown that a treatment cell with TiO2-coated electrodes can be successfully used for the PEF treatment of microorganisms: 3-log10 reduction in the yeast population was achieved with 100 impulses. The energy efficacy of the PEF process in the proposed treatment cell has been compared with the energy losses in the PEF treatment cell with uncoated, conductive electrodes. It is shown that the electrodes coated with TiO2 provide better performance as compared with the traditional uncoated electrodes.