Eur. Phys. J. D 54, 195-204 (2009)
https://doi.org/10.1140/epjd/e2009-00035-7

DC discharges in atmospheric air for bio-decontamination – spectroscopic methods for mechanism identification

¹ Division of Environmental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 84248 Bratislava, Slovakia
² Division of Biomedical Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 84248 Bratislava, Slovakia
³ Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, 84215 Bratislava, Slovakia

Corresponding author: ^a machala@fmph.uniba.sk

Received: 5 September 2008
Revised: 22 December 2008
Published online: 13 February 2009

Abstract

Three types of DC electrical discharges in atmospheric air (streamer corona, transient spark and glow discharge) were tested for bio-decontamination of bacteria and yeasts in water solution, and spores on surfaces. Static vs. flowing treatment of contaminated water were compared, in the latter the flowing water either covered the grounded electrode or passed through the high voltage needle electrode. The bacteria were killed most efficiently in the flowing regime by transient spark. Streamer corona was efficient when the treated medium flew through the active corona region. The spores on plastic foil and paper surfaces were successfully inactivated by negative corona. The microbes were handled and their population evaluated by standard microbiology cultivation procedures. The emission spectroscopy of the discharges and TBARS (thiobarbituric acid reactive substances) absorption spectrometric detection of the products of lipid peroxidation of bacterial cell membranes indicated a major role of radicals and reactive oxygen species among the bio-decontamination mechanisms.