Researchers are employing metagenomic techniques to identify microbial life onboard the International Space Station (ISS). This approach analyzes all DNA present in a sample, bypassing the need to culture or pre-identify organisms. A study by Urbaniak et al. sampled eight locations, with one experiment focusing on a sterile cloth wiped on the ISS dining table.

The raw DNA sequences underwent quality control and filtering using tools like fastp to remove errors and adapter sequences. Subsequently, the kraken2 metagenomics tool was utilized for rapid species identification. Unlike slower alignment-based methods like BLAST, kraken2 achieves speed by breaking sequences into k-mers and looking for exact matches against a curated database. The study used a Plus PF-8 database, which includes bacteria and fungi, to analyze the filtered reads.

The kraken2 analysis revealed the microbial composition of the dining table sample. The results were presented in a report detailing the number of reads mapped to each taxon. This data allowed for the visualization of microbial prevalence, with bacteria and fungi represented distinctly. The methodology, including the use of kraken2 and specific databases, offers a scalable solution for identifying microbial communities in diverse environments, not limited to space exploration.