The EDEN ISS mobile test facility microbiome changes by cleaning and continued use.

Area of Science:

• Space exploration
• Microbiology
• Bioregenerative life support systems (BLSS)

Background:

• Bioregenerative life support systems (BLSS) are crucial for long-duration spaceflight, providing essential resources for crews.
• Maintaining a healthy microbiome within BLSS facilities is vital for operational success and crew safety.
• The EDEN ISS project in Antarctica tested plant cultivation technologies for BLSS applications.

Purpose of the Study:

• To assess the microbial bioburden on surfaces within the EDEN ISS Mobile Test Facility (MTF).
• To identify potential plant and human pathogens present in the BLSS environment.
• To evaluate the effectiveness of current cleaning procedures in managing microbial contamination.

Main Methods:

• Surface swab samples were collected from the MTF during various experimental campaigns.
• Viable counts were used to estimate surface bioburden.
• Isolates were identified using partial 16S rRNA gene sequencing.
• 16S amplicon sequencing was performed on extracted DNA for comprehensive microbiome characterization.

Main Results:

• Cleaning procedures did not significantly reduce microbial bioburden across different sampling locations.
• Both isolate identification and microbiome analysis revealed the presence of environmental genera.
• Genera including potential pathogens like *Pseudomonas* and *Acinetobacter* were identified, comprising up to 16.1% of reads in some samples.
• Limited overlap between sequencing methods highlighted the benefit of a combined approach for thorough microbiome assessment.

Conclusions:

• The current cleaning regime in the EDEN ISS MTF is insufficient for effective bioburden reduction.
• The presence of pathogens poses a risk to plant health and potentially crew safety in space-based BLSS.
• Integrated sequencing approaches provide a more complete understanding of the BLSS microbiome, essential for risk mitigation.