Who's Who at NASA

Dr. Leslie Bebout works as a microbial ecologist in the Exobiology Branch at NASA’s Moffett Field, CA-based Ames Research Center. She and her colleagues study the complexities of carbon, nitrogen and hydrogen cycling in early Earth and Mars analog microbial systems. They concurrently are using this systems biology approach to work with engineers to design systems geared to optimize the use of water, light and nutrient resources relevant both to the development of new green technologies and space exploration capabilities.

NASA Tech Briefs: What does a microbial ecologist do?

Dr. Leslie Bebout: We started studying microbes because they are the earliest forms of life on planet Earth. They’re also what we’re looking for, either remnants of cells themselves or indicators that they were there on Mars. We also look at gases in the atmospheres of far distant planets to see if we get indications of life processes there. That’s the historical basis for study of microbiology and microbial ecology at NASA.

On Earth, the many transformative properties of microbes are critical; one example is that the cyanobacteria developed the process of photosynthesis. People overlook how profound this is. Photosynthesis is the conduit by which a huge amount of solar energy hitting Earth gets transformed from electromagnetic energy into chemical energy. Basically, this is what makes Earth different from the other planets. It’s the capture of light energy into chemical bonds that are continuously broken, reformed and transformed.

Microbes are fantastically diverse, and they carry out transformations that literally run the planet. All of our oxygen, all of our carbon, all of our nitrogen, all of our hydrogen goes through these microbial pathways, and it’s a profound life support system. We wouldn’t be here if it wasn’t for these microbial processes.

In recent years, because of the transformative and pivotal roles of microbes, they’ve become increasingly interesting, especially in the field of green energy. They produce lipids, and the majority of our petroleum —diesel, kerosene, and gasoline — all have microbial origins. Microbes also produce hydrogen, oxygen and methane.

For space applications, about 20 or 30 years ago, there was a lot of emphasis on using this biological support to keep humans alive in space. However it was found to be challenging to do consistently. It was complicated, and similar to if you have a fish tank, things don’t always go the way you want them to.

Therefore those biological system efforts were abandoned in favor of more short-term physical and chemical methods for life support, which had high reliability and were very well-defined, and those have worked really well. The problem there is re-support. It costs about $10,000 to get a standard bottle of water into space. If you are going out longer than a year or more, you have to start recycling, as it will be difficult to even re-support your physical and chemical systems fully.

So, scientists are stepping back towards thinking about biology for life support; and now we have a lot more tools at our disposal to make biology work together with the engineering approaches. This is still in the distant future, but we have to start taking steps now to be ready for that scientific approach. Biological systems need to integrate with engineering to work well together.

NTB: Is that what you’re working on now? Or is there more of an emphasis on green technology?

Bebout: Our day job is still the basic microbiology for astrobiology-exobiology; that’s our core. But during these past few years, we’ve also been working with folks at Lawrence Livermore National Laboratory (LLNL), with funding from the Department of Energy, to look at hydrogen cycling in these microbial ecosystems. We were able to use their technologies and tools that we don’t have at NASA, and that’s been a really good partnership. That project is about a third of our time; exo-biology-based projects are still done about 50 percent of the time; and during the remaining time we want to reach out into these other areas, such as looking at modern-day fuel needs, and where NASA technologies or partnerships or basic biology knowledge could be useful.

NTB: Can you say more about the modern-day fuel needs?

Bebout: Five or six years ago, we began talking to people in the industry. We talked to as many commercial growers as we could, and as many people in different academic and federal labs. I think at that point there might have been a little perception of “Why is NASA interested in this? Is it jumping on the bandwagon?” Many times I said, “No, We’ve been studying these microbial transformations for a long time, and we want to use them eventually for space applications. So if there are things that we know that can be helpful, we want to provide that knowledge.”

In the other sense, we want to see what is happening now that this area has exploded in the past 10-15 years, to see what developments have happened that we can pull back for NASA mission needs as well. Those contacts have remained viable, and we keep in touch with people in the industry and also at other federal labs. We’re just keeping the awareness level up.

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