Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Timothy Kral

Committee Member

Mack Ivey

Second Committee Member

Dan Lessner

Third Committee Member

Andrew Dowdle

Abstract

Because of asteroids’ chemical features, they may serve as potential environments for life and are of interest in astrobiology. Dr. Kral’s laboratory studies methanogens, microorganisms in the domain Archaea, as possible life forms on extraterrestrial bodies. Since some methanogens can withstand harsh environmental conditions and produce methane as a waste product, methane production can be used as an indicator of potential microbial activity.  In this study, three methanogen species, Methanothermobacter wolfeii, Methanobacterium formicicum, and Methanosarcina barkeri were tested for growth on asteroid simulants based on the Orgueil (CIE-1) and Murchison (CME-1) meteorites. First, methanogen growth was assessed in the presence of asteroid simulants combined with standard growth media to determine if the simulants were inhibitory. It was determined that M. wolfeii, M. formicicum, and M. barkeri could grow on both asteroid simulants in growth media. Secondly, washed cells were inoculated onto simulants without media to determine whether the simulants could serve as sole nutrient sources except for water, carbon dioxide, molecular hydrogen and sodium sulfide. Methane concentrations were measured using gas chromatography to determine growth and metabolic activity over time. Results indicate that methanogens can survive and, in some cases, grow on asteroid simulants, demonstrating the resilience of these organisms and suggesting that asteroid-like environments could potentially support microbial life.

Keywords

asteroids; methanogens; panspermia

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