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Dr. Mary Lidstrom, is Professor Emeritus of Chemical Engineering and Professor Emeritus of Microbiology at the University of Washington. She is an acknowledged leader in the methanotroph field globally, where she has been active for 50 years and is now committing her life’s work to lead this project. Here she discusses the enormous potential of these bacteria to slow global warming and explains why they are so close to a major breakthrough in the race to reduce methane. 

Tell me about your project 

This project that has been funded by CTRF is focused on an important issue of climate change, which is the methane going into the atmosphere. Methane is a very potent greenhouse gas and our technology is biologically based technology to remove methane from air with a focus on extremely low concentrations of methane in the two to ten parts per million range.  

Could you explain about the potency of methane 

Methane is much stronger in terms of global warming than CO2. It contributes right now around 30% to the total amount of global warming and on a weight basis, a ton of methane on a 100 year time scale is over 30 times more powerful than a ton of CO2 in global warming. 

If you look at a 20 year time scale, it’s over 80 times more potent. So removing methane is a way to impact global warming at a higher scale than removing CO2. We still need to remove CO2 but removing methane gives us a kind of a leg up to slow global warming in the short term.

What are the sources of methane that this might tackle? 

There are many sources of methane around the globe. Some of them are natural, so wetlands are a big source and tundra as it begins to melt. But somewhere on the order of half of the methane emitted, is coming from human caused activities. Some of the specific sites and categories that emit methane are landfills, coal mines, oil and gas wells, are all leaking methane into the atmosphere. Also rice paddies, agriculture in general, but especially manure management –  there is a lot of methane coming out of any livestock cultivation. 

Can you explain how methantrophic bacteria work and what your focus is? 

These bacteria that consume methane are basically eating the methane. It’s their main nutrient source. They are unique in their ability to consume methane and they are very widespread and pretty much everywhere. They’re in your garden soil, they’re in lakes and streams and they’re in the oceans, they’re up in the tundra and in the wetlands. They do this naturally, and many of them have the ability to use methane at quite low concentrations, which is an advantage as we think about trying to harness their ability.  Now, our technology is not about trying to manipulate their natural activities out in a natural environment because in those environments they’re actually mostly limited by the amount of methane present, so the only way to really stimulate them a lot is to add more methane, and of course that’s not what we want to do.  

So we’re proposing a closed system technology, a box that is called by a bio-reactor which has modular systems, such as trays or filters or other systems that hold the bacteria. The air containing the methane is pumped through these systems and the bacteria naturally use it. Then the air that goes out is cleaned of the methane. 

Part of the methane gets converted to CO2 but that’s actually okay because there is a big difference in the global warming potential of methane and CO2 so every molecule of methane that gets converted to CO2 is a big win. But about half of the methane gets converted into more cells. The bacteria are eating the methane and they’re growing on it, and they make more cells and that’s called biomass and the biomass is a valuable product. It can be dried down and used as a supplement for animal feed – that’s called single cell protein. It can also be dried and used for fertilizer. Furthermore, the cells could potentially be engineered to make other products like biofuels or bioplastics. So all of this has value. It’s a co-benefit of using these organisms and really makes them more effective in using methane at these levels. 

What are the steps you need to take to achieve proof of concept that this could work at scale? 

Part of it has to do with the biology the cells themselves and part of it has to do with the bio-reactor technology, the box so to speak, and how it works. A big part of what we’re focused on is how do we get these small amounts of methane that are in the air more effectively to the cells. For that the methane has to dissolve in a film of water and it’s not very soluble in water. This is called mass transfer or mass transport so we’re focused on increasing that so that for the same amount of methane, the cells actually get access to more of it. In some ways it’s analogous to thinking about us eating calories. So if we have 5000 calories a day open to us, we obviously do quite well, 2000 we’re probably doing okay, if we get down to 1000 calories a day and now it’s starting to get tough. As we go lower and lower, it makes it much harder to exist. It’s the same concept for the bacteria as the amount of methane they have gets lower and lower and more dilute. Methane is their food and if they don’t have enough to eat, they’re basically starving.  

So what we’re focused on is how do we get more of that methane to the cells so they’re not starving quite so much. We have ideas of how to do that by manipulating the bacteria themselves and other ideas of how to do it, by manipulating the design of this bio-reactor and how the air comes in and how it flows across the cells. So those are the two main categories. We are doing some pretty high level biochemistry on the methane consumption enzymes, both with computational simulation and with manipulation of the enzyme itself.    

What is the potential to scale up and reply globally ?      

So initially we would target these high concentrations, but the goal is to be able to get to wetlands and the tundra, which out in the future are looking to be very serious issues with regard to methane emissions. So we’re looking more in the ten parts per million. The methane that we breathe in our air is two, so this is very low. In that 2 to 10 parts per million range, that’s where we want to get to because these sources of methane, where it’s at this low concentration are going to be more and more important as time goes on for global warming.        

Depending on the kind of site, this might be a system, the whole system about the size of a shipping container.  We envision it being mobile using very low power and positioned near these sites. Another possibility is that we would take advantage of systems that are already moving a lot of air. So, for instance, in livestock barns often there are large fans, large ventilation systems, so they’re moving a lot of  air. 

It’s the same with the CO2 capture systems that are being envisioned.  These could be placed downstream to receive the air where the CO2 has been removed, but the methane is still there. And so those would all take advantage of air movement that’s already taking place, and that would make them much more efficient. Eventually what we envision are relatively small scale units that would go into a building where there would be air handling, there’d be a ventilation system so maybe all new buildings would have one of these installed, just like we have recycling today and eventually trying to get to a household level version. That would be the future.  

How does this build on the work that you’ve done so far? 

There is a long history of work in this field. I myself have been working with these organisms for 50 years. I have been endlessly fascinated with them because the ability to grow on such a simple, inert compound like methane has always intrigued me and fascinated me and as we learn more and more, we discover that there are incredibly complex layers of the biology, the biochemistry, the genes that are involved in this. But until very recently, no one has ever looked at the ability of these bacteria to grow at these very low methane concentrations, even though it’s been known for decades that they do. It’s those mechanisms, the understanding of how they do this, that once again, I find these bacteria giving us all kinds of interesting insights and a whole new area that we have never looked at before, but it’s all built on the foundation of our understanding, our deep understanding of these organisms and how they grow on methane. 

It has caught the attention of a number of groups and so we’re going to see a lot of breakthroughs coming in the next few years, I believe. Again it’s a wide open field. No one’s ever looked at this before and we’re beginning to gain a lot of insights.  

Why is it valuable that this is a closed system approach ? 

So we’re focused on a closed system, something we can control. There are process reasons why that’s useful but there’s also a de-risking as the risk of these organisms causing environmental damage gets decreased. It is known that in natural ecosystems, take rice paddies for instance, where methane is being produced, when the activities of these methane eating bacteria are stimulated, it causes changes in the natural microbial communities such that another greenhouse gas actually increases. That greenhouse gas is N2O – nitrous oxide. It’s actually ten times worse than methane in its global warming potential and so it doesn’t take much extra nitrous oxide before this starts to be an environmental problem and possibly negate the benefit of removing the methane.    

So it’s very important to ensure that whatever methane consumption by the biology that’s going on is not resulting in an increase in N2O and in this kind of closed system that we’re talking about, we can control it so that there is no N2O produced. That’s an added benefit of the closed system, it helps to keep the risk of environmental damage low. 

Is the challenge of methane levels likely to increase? 

There is an increasing concern about the current emissions of methane. Methane is increasing in the atmosphere every year but the rate of that increase is going up which is a big concern and the data so far suggests that the source of that increased methane coming into the atmosphere is biological, most likely wetlands and as the earth warms up and wetlands that have been frozen, like the tundra, start to warm up  the prediction is there will be even more methane emitted from these natural sources and there aren’t any technological solutions at the moment that could be deployed to handle these emissions. 

We feel that looking out ahead  30, 50,100 years, it’s going to be vital that technologies to deal with these issues like increased methane emissions are developed now and we need the fundamental work, building on this foundation of many many decades and many many research groups. We need this basic research to use these organisms to solve these problems, to move that ability up to the next level, so it’s critical to invest now. 

We expect in the next 5-10 years we should be at a point that we should start to see deployment and that will be in time to start to slow global warming and take advantage of this system.  

How exciting is the potential? 

This project is incredibly important to me. I have, over the last three years, focused all of my effort on this. I started looking at it as a possibility about five years ago and I began to become incredibly concerned that the effects of climate change were happening much more quickly than anyone expected. We can see it starting to happen, starting to have impacts on people’s lives and I felt a huge sense of urgency to do something. I think we all do things in our households and at work to help, and I do those things but I’m an expert in methane consumption, and I felt that I could use my 50 years of experience and bring a team together and address this in a way that could help slow global warming.        

The more I work on it, the more I bring people together and we make progress, the more convinced I am that this is real, that we have an opportunity to do this. So it is my, it is what I spend all my working time doing, and I am determined that we will succeed on this. 

CTRF has funded more of your work, with more support what more could be done? 

This project is definitely limited by the amount of funding. It’s not limited by the ideas. As I explained earlier, we know what to do. And it’s not limited by the expertise. The research groups are available to carry out this work. And it’s not limited by people who are interested in it because there’s great interest in a project like this.  

If we had more funding then we could make much more progress. At the moment, we are not able to do things, to do our work in parallel. We’re pursuing a stream, getting a conclusion, moving on to the next. But we have many ideas that we could pursue in parallel if we had more funding and more people. So it would make a huge difference, it would greatly speed up getting to this outcome that we’re all working so hard to achieve. 

As a global community, we need to be investing in multiple opportunities. But this nature based solution has so many advantages. And if we can get it to work, I believe it’s the real solution, for the next 100 years.  

The Earth needs to be moving towards more nature based solutions for all of our resource issues and this is so tantalizingly close. I feel that we are not that far away from making the breakthroughs to make this work.

Once we get it moving, it will advance. The technology will be enhanced, it will get better and better. But now is the exciting time as we get this  launched and ready to deploy and make a difference.