Abstract:
Komagataeibacter is the dominant taxon and cellulose-producing bacteria in the
Kombucha Microbial Community (KMC). This is the first study to isolate the K. oboediens
genome from a reactivated space-exposed KMC sample and comprehensively
characterize it. The space-exposed genome was compared with the Earth-based
reference genome to understand the genome stability of K. oboediens under
extraterrestrial conditions during a long time. Our results suggest that the genomes
of K. oboediens IMBG180 (ground sample) and K. oboediens IMBG185 (spaceexposed) are remarkably similar in topology, genomic islands, transposases, prion-like
proteins, and number of plasmids and CRISPR-Cas cassettes. Nonetheless, there was
a difference in the length of plasmids and the location of cas genes. A small difference
was observed in the number of protein coding genes. Despite these differences, they
do not affect any genetic metabolic profile of the cellulose synthesis, nitrogen-fixation,
hopanoid lipids biosynthesis, and stress-related pathways. Minor changes are only
observed in central carbohydrate and energy metabolism pathways gene numbers or
sequence completeness. Altogether, these findings suggest that K. oboediens maintains its genome stability and functionality in KMC exposed to the space environment most
probably due to the protective role of the KMC biofilm. Furthermore, due to its unaffected
metabolic pathways, this bacterial species may also retain some promising potential for
space applications.
