Thirteen strains of a novel spore-forming, Gram-positive, mesophilic heterotrophic bacterium were isolated from spacecraft surfaces (Mars Odyssey Orbiter) and assembly-facility surfaces at the Jet Propulsion Laboratory in California and the Kennedy Space Center in Florida.
...
Studies have repeatedly shown that extremely resilient, spore-forming members of the genus
Bacillus are the most strongly represented micro-organisms in samples collected from spacecraft and facility surfaces (
La Duc et al., 2003;
Puleo et al., 1977). The extremely oligotrophic, low-humidity, temperature-controlled conditions of spacecraft-assembly facilities appear to select for micro-organisms able to withstand such unfavourable surroundings. During monitoring of the microbial diversity of spacecraft-associated environments over a period of 5 years (1999–2004),
Bacillus pumilus was found to be the second most dominant species among the aerobic spore-forming bacteria (the predominant species being
Bacillus licheniformis;
La Duc et al., 2004a). Several of these
B. pumilus isolates have exhibited elevated resistance to H[SUB]2[/SUB]O[SUB]2[/SUB] (
Venkateswaran et al., 2001;
Kempf et al., 2005) and are thus considered as ‘problematic’ micro-organisms, since H[SUB]2[/SUB]O[SUB]2[/SUB] is recommended for the bioreduction of spacecraft components.
