Importance of the substrate nature to preserve microorganisms' cultivability in electrostatic air samplers. (September 2015)

• Record Type: Journal Article
• Authors: Roux, Jean-Maxime; Rongier, Anaëlle; Jary, Dorothée
• Is Part Of: Journal of physics. Number 646(2015)
• Publication Date: 2015-09
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/646/1/012039
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Recent research shows that electrostatic precipitation is a gentle method to collect airborne microorganisms and preserve their cultivability. However, the corona discharge used to charge the particles and the high electric field used to capture them are known to have a germicidal effect. The present paper investigates this paradoxical situation. Vegetative cells of E. coli and B. subtilis and spores of A. fumigatus and B. subtilis were deposited on different media and subjected to electrostatic fields of different strengths and polarities for controlled time periods. Vegetative cells are inactivated on cultivation agar plates, but remain cultivable when exposed on a stainless steel electrode and transferred afterwards onto agar plates. For the investigated conditions, spores were not affected by the corona discharge. Further experiments with a pH indicator show that chemical reactions occur when an aqueous media is exposed to the discharge. Some of these reactions are likely to create hydrogen peroxide which is known to kill a broad range of microorganisms. It is therefore highlighted that collecting electrodes in electrostatic air samplers should rather be dry conductive media.