Faculty Mentor

Dr. Justin Bastow

Document Type


Publication Date

Spring 6-3-2022




Escherichia coli, Bacillus subtilis, and Staphylococcus aureus are all known spacecraft contaminants. This makes their viability to arrive and survive on Mars feasible, however, this could prove to be a great risk to the Martian environment. In order to test this possibility, all three species were grown within brines containing differing salts and salt concentrations. These salts and their corresponding concentrations are based on known data regarding Martian soil. Growth was measured over a course of 20 hours in solutions containing MgSO4 at concentrations of 4.6% and 9.2%, Mg(ClO4)2 at concentrations of 0.6% and 1.2%, as well as solutions containing both salts at 4.6%/0.6% and 9.2%/1.2% (concentration of MgSO4 / concentration of Mg(ClO4)2). Significantly reduced B. subtilis growth to the point of possible cell death was present in all salt solutions except for Mg(ClO4)2 at 0.6% where growth was present. Normal levels of growth across all salt solutions were present with S. aureus except for solutions containing all salts at double concentrations. Similarly, normal levels of E. coli growth were reported within all salt solutions except for Mg(ClO4)2 at 0.6% where a significant increase in growth was reported. Our results suggest that a combination of a lack of sulfide toxicity and the presence of perchlorate reduction may be a necessity for future microbial life on Mars.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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Bacteriology Commons