Dr. Leslie Bebout, Microbial Ecologist, Ames Research Center, Moffett Field, CA
- Created: Tuesday, 01 October 2013
NTB: What is a typical day for you?
Bebout: It’s kind of variable with time of year. There’s always an emphasis on working on our funded projects and making progress on them. But at other times, we have to mix in a focus on proposals for new funding.
In the summer months, we have a lot of interns in the lab, 7 or more. We work with interns to either match them into ongoing projects, or in some cases, towards generating seed data in new areas that we might want to propose to in the future, but need preliminary data first.
Folks in our group also have a lot of emphasis in working with nanoSatellite platforms and looking at how you would study microbes in space, and their performance in space, so that we can use that data as we move towards applications.
NTB: What are the advantages of growing algae in space? How can the study of microbes help with future space missions?
Bebout: Microbes and microalgae could provide a lot of benefits, from being a food source to producing bioplastics or pharmaceuticals. They can use waste water, such as urea as a nutrient source, and also to absorb CO2 and produce oxygen.
Conditions are different in space, though, as far as diffusion, convective flow, microgravity, and radiation. As we get better at using these microbes on Earth, we have to study these same functionalities in space platforms where the environment is a little bit different. It might take a survey of many different species to see which microbes are best adapted to that.
The other possibility is doing a slow adaptation or targeted directed evolution. Microbes in space will start to adapt to that environment. In fact, there is some talk that all the microbes on the International Space Station, which have been thriving for years, have probably undergone adaptations. that we should be studying even more actively.
NTB: Is that where the Space PAM technology comes in, as far as measuring the efficiency of the photosynthesis in different environments?
Bebout: [With Space PAM], or space platform adapted, Pulse Amplitude Modulated Fluorometry, you can non-invasively survey a cell and tell what proportion of the light is going into production of chemical energy, versus how much is just being dispensed as fluorescence and non-usable. If the cell is stressed in any way, it will very quickly lower its photosynthetic efficiency. If it’s stressed by low nutrients or radiation damage or something like that, you could quickly see that, and as it recovers, you can non-invasively see that the cells are healthy. So it’s a really quick monitor.
NTB: How does microbial research impact atmospheric studies?
Bebout: This is not really my area, but as I understand it, researchers will be looking at far-off atmospheres for the balance between certain gases like hydrogen, oxygen, water vapor, and other gases like methane; basically, you would expect a certain composition suite if there were only chemical processes going on. When things come to equilibrium, there’s a certain proportion you would expect, and if there’s a biological driver in the system, like on Earth, where [the bio-chemical processes are] getting sunlight, they’re going to be tweaking the balance of those different molecules, in ways that don’t make sense from a purely chemical basis. That is where you can get an indicator that there might be another process.
NTB: Will this kind of work be applicable to Mars missions as well?
Bebout: For the atmosphere, people have been looking for trace amounts of methane and trying to decipher what is going on there. But with Mars, I think the additional component is to look for what we call organic biomarkers, which are remnants of cells and cell walls in the sediment, or some of the minerals that might be influenced by microbes being there. As far as methane, there are folks in the group who are looking at the isotopes of the methane produced in extreme environments like Chile and hypersaline environments in Mexico. Isotopes can indicate that methane is formed by biological or chemical means, such as volcanic emissions. That also could have impacts on satellite monitoring of Earth’s atmosphere, to look at methane balance, because it is an important greenhouse gas. Our group has worked with the Earth sciences group to help ground-test the JAXA satellite, that looks at methane hot spots.
That’s kind of neat because you’re looking at Earth from a mega-level in space, with satellites going over and looking at the gas emissions, and then going down to the intermediate level that you can do with UAVs, and then getting to the ground level, to see what is the actual biological, chemical, or geological signal, and interpret that data for the satellite.
NTB: What is RoboAlgae?
Bebout: RoboAlgae is something that came up when we were talking to all of these commercial growers — mostly in Imperial Valley, some in Hawaii, some other local ones. Raising algae for biofuels is rather new, but there have been people raising large algae farms for nutraceuticals like Spirulina or beta-carotene for decades. We asked those growers what their bottlenecks were to becoming more productive, or going to a larger scale. At those long term operations, they know exactly what they’re doing. They know what to expect from the cells and what to watch for. They sample those systems, at rates determined from long time trial and error and get their data back in an hour to a couple of days, which will tell them if they need to change a mixing rate, or add a different nutrient, to optimize their system. But using these systems for fuel production there is an absolute requirement to further lower operations cost, and the species for lipids don’t have nearly as long of a history at mass culture, so there are still many challenges.
One of the problems for large operations is that things grow and change so fast. Imagine you had 50 acres of tomato plants, but those tomato plants grow from seed to produce full tomatoes in 4 days, and if something happened, like a pest, it could wipe out the crop in a matter of hours. And that’s basically what the situation is with algae for fuel. It’s a highly dynamic environment. It’s affected by weather and things blowing in. You need to monitor the situation in real time to head off problems. Or if it’s a situation where you can’t fix it, then you need to know early on whether to crash the system, clean up, and start again, rather than waste your time on a dying crop.
The RoboAlgae concept is a very cheap and small wireless measuring device that can be designed with various sensors, and is based in part on space nanoSatellite design elements. It is designed to float through large or small raceways, giving you a lot of data, not just from one section of your growth system. It moves through the system to give you data from a lot of different areas, so that the growers can more quickly see what’s going on in their ponds. We also have done some work with Kai Goebel and the Intelligent Systems Division, to develop prognostic algorithms, from actual trials in our greenhouse raceways. The hope would be that we could use the RoboAlgae data and prognostics algorithm software to design a useful system for growers. This would be useful because these larger operations for biofuels are newer than those traditional crops, and there are still a lot of unknowns. What you want to do is be able to head off problems down the line, and that’s what NASA prognostics are very good at. One level is get the information to the growers quickly, the second is to build prognostic algorithms to help with management decision making and these are the same capabilities we will need for reliable space platforms.