title: Effects of Low-Temperature Plasma-Sterilization on Mars Analog Soil Samples Mixed with Deinococcus radiodurans.
abstract: We used Ar plasma-sterilization at a temperature below 80 °C to examine its effects on the viability of microorganisms when intermixed with tested soil. Due to a relatively low temperature, this method is not thought to affect the properties of a soil, particularly its organic component, to a significant degree. The method has previously been shown to work well on spacecraft parts. The selected microorganism for this test was Deinococcus radiodurans R1, which is known for its remarkable resistance to radiation effects. Our results showed a reduction in microbial counts after applying a low temperature plasma, but not to a degree suitable for a sterilization of the soil. Even an increase of the treatment duration from 1.5 to 45 min did not achieve satisfying results, but only resulted in in a mean cell reduction rate of 75% compared to the untreated control samples.
authors.affiliation: Astrobiology Research Group, Center for Astronomy and Astrophysics, Technical University Berlin (TUB), Berlin 10623, Germany. j.schirmack@tu-berlin.de.
authors.forename: Janosch
authors.initials: J
authors.lastname: Schirmack
authors.affiliation: Biomedical Applications of Plasma Technology, Institute for Electrical Engineering and Plasma Technology (AEPT), Ruhr University Bochum (RUB), Bochum 44801, Germany. fiebrandt@aept.ruhr-uni-bochum.de.
authors.forename: Marcel
authors.initials: M
authors.lastname: Fiebrandt
authors.affiliation: Biomedical Applications of Plasma Technology, Institute for Electrical Engineering and Plasma Technology (AEPT), Ruhr University Bochum (RUB), Bochum 44801, Germany. stapelmann@aept.ruhr-uni-bochum.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Stapelmann
authors.affiliation: Astrobiology Research Group, Center for Astronomy and Astrophysics, Technical University Berlin (TUB), Berlin 10623, Germany. dirksm@astro.physik.tu-berlin.de.|School of the Environment, Washington State University, Pullman, WA 99164, USA. dirksm@astro.physik.tu-berlin.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schulze-Makuch
keywords: Deinococcus radiodurans; Mars; plasma sterilization; regolith