EPISODE 135: BIOFILM – DEALING WITH THE SCUM OFF THE EARTH

Transcript

Andrés Almeida (Host): Welcome to Small Steps, Giant Leaps, your NASA APPEL Knowledge Services podcast where we dive into the lessons learned and real-life experiences of NASA’s technical workforce. I’m your host, Andrés Almeida. 

Imagine you’re on a deep space mission and suddenly the system that gives you fresh and clean water… clogs up? There’s probably a thick layer of biofilm in the way. Biofilm is the slimy buildup of bacteria or fungi. On Earth, it can be costly and cumbersome to take care of, but dealing with it aboard spacecraft has its own unique set of challenges. So how can we prevent that mucky buildup in the first place? NASA researchers are looking at how to keep biofilm from becoming the scum off the Earth. And some novel ideas could potentially be used right here at home.  

On this episode, we’re talking with Yo-Ann Velez Justiniano, a microbiologist and systems engineer at NASA’s Marshall Space Flight Center in Huntsville, Alabama. She and a small team of scientists are looking at innovative ways to prevent biofilm from occurring. 

Host: Hey, Yo-Ann, thank you for joining us today. 

Velez-Justiniano: Thank you for having me here. 

Host: Can you tell us what makes biofilm so challenging to deal with in space? 

Velez-Justiniano: So, that is kind of a tricky question because I think that biofilm is also difficult to deal with on Earth. Space just gives it an extra layer of difficulty, because the systems are so far away from us down here. You know, right now with ISS and the future with Gateway, and other space systems to get to Mars, there will not be that fast turn around, when astronauts ask for help. And so a part of figuring out how to mitigate biofilm is also how to make it so that the astronauts are able to use these new capabilities and new technologies for long-term duration missions. 

Of course, there’s the aspect of how the genetics of some of these organisms may change in microgravity, right, and space travel, and that sort of thing. But the extra layer comes from there not being that added ground support for the astronauts. And so we want to get the systems that they use to a point in which they’re almost perfect, right? I don’t think there’s such a thing as a perfect system, but almost perfect to the point that they will not need that support from ground to live and to get their water and oxygen. And that’s my, my specialty, I guess, with the ECLSSin case I didn’t mention it. That’s Environmental Control and Life Support Systems. And so that’s what’s keeping the astronauts alive in space right now and ISS. 

Host: Speaking of ISS, you and your team sequenced the genomes of several bacterial strains that were returned to Earth from the space station. What have you learned from that? 

Velez-Justiniano: Well, we have learned some similarities and differences to the organisms here on Earth. Overall, they are very similar. Some of the changes come from, perhaps come from some of the mobile genetic elements. And that is something that we have not looked into deeply, but we can already start to see some of those different configurations and the genomes. But we have, I think, at least two papers out there, describing the genomes of some of these organisms. And for the most part, they are very similar. And that’s actually very scary, because that means they have all the basics already to form some, some good biofilm. And to move around the water processors, suddenly, these are water bacteria, right? 

And so these organisms, as I was saying, there, they look kind of similar to the ones on Earth. And we are going to put out another study, which is more of a longitudinal assessment. And what that means is, over the years, how they have moved through system and how they appear in different parts, at different time points and ISS. And that to me was very interesting to study because we see at least one of these organisms surviving through most of the current components and the water processor assembly. 

Host: And have you found that they have been resilient and able to adapt to different environments? 

Velez-Justiniano: So, they are very resilient. And just with the basics, and they’re own genomes, they are very resilient in space and they form their own communities right and we have been able to just study them here at Marshall Space Flight Center a little bit further inside bioreactors and more long-term studies. The one aspect that we’re missing is the including microgravity in the ground tests. And so that is something that we look forward to doing kind of seeing how the microgravity aspect affects these microorganisms in a vacuum, right?  

And right now as they are, they’re in a community and water, right? So we have to start to pull out those variables separately, and kind of define them. And they’re all very different. They cause biofilm. But all of these organisms are very different. And that’s something else. We’re looking into comparing the different species to each other and see what parts overlap, what parts don’t overlap. 

Host: Can you tell us about how you studied these strains with support of the CDC? 

Velez-Justiniano: So, we have this thing called the biofilm test stand inside our biofilm lab at NASA Marshall. And it is around 10 bioreactors filled with what we call our erzats, and that is wastewater simulant. So, we tried to mimic that the same nutrient conditions that are in the water in ISS. And we pass these erzats through clean, sterile CDC bioreactors. The bioreactors themselves contain what we call coupons. These are just little round sections of material, right? We can test different materials in there. And then the Earth sets is inoculated with these ISS microorganisms. And we try to get it to the same concentration that they exist in ISS currently.  

And we do long-term studies. We do around nine to 12 weeks at a time. And we let these microorganisms grow in the bioreactors. And so we’re able to study the biofilms that they form. How much of it if we’re able if some of the technologies that we have in these bioreactors is able to mitigate the biofilm to what extent we’ve noted other behaviors such as shifting of the biofilm, upstream or downstream the bioreactor. Maybe the method is useful on the bioreactor bulk water itself. But the biofilm may shift to other places. And so, that is how we have used the CDC bioreactor to study biofilm right. 

Host: So, historically, how have we dealt with biofilm at the space station? 

Velez-Justiniano: Currently, the way NASA deals with biofilm on ISS is by either flushing the system, changing parts, exchanging certain parts that may be clogged. And that’s a way that they clean out the system right now. And so, it’s like when your toilet clogs, and you have to come in and open the lid or use certain equipment to unclog it. But there is no current actual mitigation option for the parts that we’re talking about, in this case, the wastewater tank to combat biofilm in that area.  

There are some other parts that combat microbial growth, right? Because at the end of the water processor assembly, we just want to have potable water that the astronauts can drink. And that is something that the JSC (Johnson Space Center) guys work on in Houston, and keeping that water clean so the astronauts can drink it. There’s some multi-filtration beds. They will add iodine solution in the line. And so, there’s some cleanliness methods, and they have some requirements. But there’s no requirements, and no methods to mitigate biofilm upstream. More, it’s happening near the wastewater tank. 

Host: So could some of the biofilm mitigation techniques be applied on Earth? 

Velez-Justiniano: Yes, absolutely. And all of the stuff that we’re trying right now, inside the bio reactors are methods that are used currently on Earth, and that are recommended by some industries and academia. And we leverage all of that, for potential in-space uses, right? So, we have worked with the Montana State University, the Center for biofilm engineering, other companies, right? And they have come up with many ideas that we can start to introduce into our larger test stand, and try to choose from a bunch of different technologies to mitigate biofilms in space. So, if we get these to a strong enough TRL, right, because the next phase of testing would be in sort of more of a system level testing, then we get those results and publish them. And hopefully the community can use that also to mitigate biofilm in current waste treatment plants on Earth. 

Host: Can you talk about collaborating with other teams across NASA and industry? 

Velez-Justiniano: Yes, we have the Biofilm Working Group. We meet every two weeks. And so in there, we have people from KSC (Kennedy Space Center) and JSC that support the biofilm mitigation efforts. We have this center for biofilm engineering in Montana that attends meetings. The work that JSC and KSC do is also attached to their own partners external partners. 

And the, from the industry, we have people from Sandy Wave, which is a company out of Georgia, and they work mitigating biofilm that occurs on human wounds, right? And some of these technologies can be applied for the biofilms that we’re studying as well. 

Host: That’s good to know. What do you see as the next step in biofilm mitigation and prevention research? 

Velez-Justiniano: Well, the next steps for research, I say are, we have to answer some of the science questions that we’ve encountered. Because as we keep studying the biofilm, we learn that we know less than we thought we did. And for a long time, I think this was just not a topic of discussion. And now that we have made it into this collaborative effort, and we have put the work into it. Now we’re starting to evolve it into something, something bigger, right? And so more questions arise. Some of these are, for example, related to the fungal biofilm. So, bacteria are not the only guys that exist in the water, we also have fungi. And, and these guys behave in a completely different way. And it is very difficult to measure them and get a grasp of how they behave in a community with the bacteria. And so I think that is something that we really have to look into as well before we continue on maturing some of these technologies, whether they’re able to combat these fungal structures and how we’re measuring them, if we’re being accurate in our measurements, and how academia can help with this. 

Host: How did you all or how did your team decide to experiment with duckweed to control biofilm growth? 

Velez-Justiniano: So that idea was presented by Eric Beitle who is our test engineer for the biofilm test stand. And it is a collaboration with some guys down at Ames [Research Center]. And they have their own bigger project related to duckweed and some of the NASA missions. And we have started to play around with the idea of using biology itself to combat biofilm, because we had focused for a long time on the material science and chemistry aspects. So we’re trying to delve into a different collection of mitigation methods that are more guided towards using biology.  

So Eric thought, you know, duckweed grow on ponds, potentially sucking up some of the nutrients, right? And he made up this pond and it’s currently growing duckweed. And the way it works is it sucks up some of the nutrients in that pond area. And then downstream, the biofilm kind of suffer a little bit. They don’t have what they need to grow. Right now we’re thinking of studying also what microbial organisms exists in the pond itself or attached to the duckweed.  

And that’s how it came to be, you know, he just, “Hey, this is going on in a different center. Why don’t we include them? Why don’t we do this with them?” They already have some projects ongoing. You know, maybe that’s something that can be used for our gain, right? 

Host: Yo-Ann, before we close out, what was your giant leap?

Velez-Justiniano: Well, I came here to Huntsville, Alabama, right before Hurricane Maria hit Puerto Rico, and I think that was a huge leap. Just that. For me to adapt to the new environment and then start work at NASA – it was incredible. It was very difficult, but you know, if these biofilm can grow in space, why can’t I do this giant leap?

Host: Wonderful sentiment. Yo-Ann, thank you for joining us today. 

Velez-Justiniano: Thank you for having me! 

Host: That’s it for this episode of Small Steps, Giant Leaps. For more on this topic and on Yo-Ann, visit our resource page at appel.nasa.gov. And don’t forget to check out our other podcasts like Houston, We Have a Podcast and Curious Universe. Thanks for listening.