Bacterial byproducts may help stop the stink in future spacesuits

European space researchers are turning to an interesting place to find new antimicrobial coatings to keep the insides of future space suits from becoming stinky, bacteria-laden biohazards: the bacteria themselves.

Everyone who's had to keep a kitchen or bathtub clean is familiar with prodigiosin - it's the pink gunk produced by bacteria that dirties up surfaces and bathroom grouting at, well, a prodigious rate. Many are likely less familiar with the fact that prodigiosin is itself an antimicrobial agent, but researchers at the Austrian Space Forum (OeWF) are well aware of its usefulness. 

As such, the OeWF has made prodigiosin and similar compounds the focus of their Biocidal Advanced Coating Technology for Reducing Microbial Activity, or BACTeRMA, program to investigate new types of treatments for the inner lining of space suits as part of the European Space Agency's Planetary Exploration Textiles project. 

Also known as PExTex, the program is more broadly exploring new materials for future spacesuits that could be used for long-term missions to the Moon.

"Spacesuits will most probably be shared between different astronauts, and stored for long periods between use, potentially in favorable conditions for microorganisms," said ESA materials and process engineer Malgorzata Holynska. 

It's easy enough to keep one's underwear clean on Earth thanks to detergents, washers and dryers, "but in habitats on the Moon or beyond, washing spacesuit interiors on a consistent basis may well not be practical," Holynska noted. Thus, "we needed to find alternative solutions to avoid microbial growth."

Keeping clean with bacteria

Silver and copper are commonly added to cloth to provide antimicrobial resistance, but ESA said it is looking for alternatives over concerns the materials could tarnish over time or cause skin irritation - hence the research into using bacteria byproducts to fight funk. 

Prodigiosin and another compound being researched as part of BACTeRMA, violacein, a purple pigment produced by another strain of bacteria, are what's known as secondary metabolites. All sorts of organisms, from plants and bacteria to fungi and animals, produce secondary metabolites to protect themselves against competing organisms and other environmental factors. 

OeWF, together with the Vienna Textile Lab, which has a "unique 'bacteriographic' collection," have been working to dye cloth with metabolites including prodigiosin and violacein. The material is then subjected to space-like conditions including radiation, moondust and simulated human sweat to see how well they work. 

ESA said the results provided "valuable insights into the effectiveness and suitability of antimicrobial substances on various textile materials."  

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OeWF director Gernot Grömer said the materials coming out of BACTeRMA are currently being integrated into the OeWF's spacesuit simulator, and may undergo their first field test this coming March as part of a simulated Mars mission set for next year in Armenia.

"The findings of PExTex and BACTeRMA lay the foundation for future developments in the areas of antimicrobial treatments and the integration of smart textile technologies," Grömer said. 

The org told The Register: "In the BACTeRMA project, we are primarily testing two compounds: prodigiosin and violacein, on three different textile choices nylon (spandex), lyocell, and Merino wool. The compounds are derived from bacterial secondary metabolites and have shown potential antimicrobial properties."

It confirmed the plan is to "explore the potential of using these compounds as microbial textile dyes for the spacesuit lining" itself – as in the "innermost layer, also known as the undergarment," which is in direct contact with the astronauts' skin.

The OeWF told us today: "By incorporating these antimicrobial substances into the fabric of the innermost layer of the space suit which has direct contact with astronauts' skin, we aim to confer antimicrobial properties to the textiles, which can help reduce or terminate microbial strains on the suit." ®