Table 6.
Summary of proposed survival strategies of the isolates and their possible origin
| Isolated microbial genus | Possible origin | Proposed survival strategy | References |
|---|---|---|---|
| Bacillus | HA, CR, ISS | Endospores | [77–83] |
| Paenibacillus | CR, ISS | Endospores | [78–81] |
| Salinibacillus | HA, ENV | Endospores | [40, 84] |
| Micrococcus | HA, CR, ISS, IA | Intrinsic desiccation resistance | [81, 82, 85–88] |
| Cupriavidus | CR, ISS | Various DNA-repair mechanisms; adapted to extreme, metal-rich, anthropogenic environments | [78, 89] |
| Methylobacterium | CR, ISS, IA | Intrinsic desiccation resistance | [5, 14, 20, 82, 90] |
| Bradyrhizobium | CR, ISS | Intrinsic desiccation resistance | [5, 14, 20, 81, 82, 91] |
Legend: HA human-associated; CR reported in spacecraft assembly clean room(s) before; ISS reported in ISS before; ENV environmental; IA indoor air