NASA researchers battle biofilm in space

A small group of scientists on the biofilm mitigation crew at NASA’s Marshall House Heart in Huntsville, Alabama, research options to fight fast-growing colonies of micro organism or fungi, often called biofilm, for future space missions.

Biofilm happens when a cluster of micro organism or fungi generates a slimy matrix of “extracellular polymeric substances” to guard itself from opposed environmental elements. Biofilm may be discovered practically anyplace, from the gray-green scum floating on stagnant pond water to the pinkish ring of residue in a unclean bathtub.

For medical, meals manufacturing, and wastewater processing industries, biofilm is commonly a expensive subject. However offworld, biofilm proves to be much more resilient.

“Micro organism shrug off most of the challenges people cope with in space, together with microgravity, pressure changes, ultraviolet light, nutrient ranges, even radiation,” mentioned Yo-Ann Velez-Justiniano, a microbiologist and environmental management methods engineer at Marshall.

“Biofilm is icky, sticky—and arduous to kill,” mentioned Liezel Koellner, a chemical engineer and NASA Pathways intern from North Carolina State College in Raleigh. Koellner used refined epifluorescence microscopy, 3D visualizations of 2D pictures captured at totally different focal planes, to fine-tune the crew’s research.

Keenly conscious of the potential hurdles biofilm might pose in future Artemis-era spacecraft and lunar habitats, NASA tasked engineers and chemists at Marshall to check mitigation methods. Marshall constructed and maintains the Worldwide House Station’s ECLSS (Surroundings Management and Life Assist System) and is growing next-generation air and water reclamation and recycling applied sciences, together with the system’s wastewater tank meeting.

“The wastewater tank is ‘upstream’ from most of our built-in water purification strategies. As a result of it is a wastewater feed tank, micro organism and fungus develop nicely there, producing sufficient biofilm to clog circulate paths and pipes alongside the route,” mentioned Eric Beitle, ECLSS check engineer at Marshall.

Thus far, the answer has been to tug and change outdated {hardware} as soon as components grow to be choked with biofilm. However engineers wish to keep away from the necessity for such techniques.

“Even with the power to 3D-print spare components on the moon or Mars, it is sensible to search out methods that stop biofilm buildup within the first place,” mentioned Velez-Justiniano.

The crew took step one in June 2023 by publishing the complete genome sequence of a number of strains of micro organism remoted from the space station’s water reclamation system, all of which domesticate biofilm formation.

They subsequent designed a check stand simulating circumstances within the wastewater tank about 250 miles overhead, which allows simultaneous research of a number of mitigation choices. The rig housed eight Facilities for Illness Management and Prevention biofilm reactors—cylindrical units roughly the scale of a runner’s water bottle—every 1/sixtieth the scale of the particular tank.

Every bioreactor holds as much as 21 distinctive check samples on slides, bathed repeatedly in a circulate of actual or ersatz wastewater, timed and measured by the automated system, and carefully monitored by the crew. Due to the compact bioreactor measurement, the check stand required 2.1 gallons of ersatz circulate per week, repeatedly trickling 0.1 milliliters per minute into every of the eight bioreactors.

“Basically, we constructed a group of tiny methods that every one needed to allow minute modifications to temperature and stress, keep a sterile surroundings, present autoclave performance, and run in concord for weeks at a time with minimal human intervention,” mentioned Beitle. “One phase of the check sequence ran nonstop for 65 days, and one other lasted 77 days. It was a singular problem from an engineering perspective.”

Completely different floor mitigation methods, upstream counteragents, antimicrobial coatings, and temperature ranges had been launched in every bioreactor. One promising check concerned duckweed, a plant already acknowledged as a natural water purification system and for its means to seize toxins and management wastewater odor. By devouring vitamins upstream of the bioreactor, the duckweed denied the micro organism what it must thrive, decreasing biofilm progress by as much as 99.9%.

Over the course of the three-month testing interval, groups eliminated samples from every bioreactor at common intervals and ready for research beneath a microscope to make an in depth rely of the biofilm colony-forming models on every plate.

“Micro organism and fungi are good,” mentioned Velez-Justiniano. “They adapt. We acknowledge that it’ll take a mixture of efficient biofilm mitigation strategies to beat this problem.”

Biofilm poses as an impediment to long-duration spaceflight and prolonged missions on different worlds the place alternative components could also be expensive or troublesome to acquire. The biofilm mitigation crew continues to evaluate and publish findings, alongside educational and trade companions, and can additional their analysis with a full-scale tank experiment at Marshall. They hope to progress to flight tests, experimenting with numerous mitigation strategies in actual microgravity circumstances in orbit to search out options to maintain surfaces clear, water potable, and future explorers wholesome.