Biofuels and bioenergy
Transcript from the interview with ASU School of Life Sciences Professor Willem Vermaas.
Science Studio Podcast Vol 27
Transcript – [Printable PDF format]
Peggy Coulombe: Hi! This is Peggy Coulombe and welcome to Science Studio. With our growing concerns about oil dependency, climate change, and the discovery that the touted corn based fuels might actually worsen the situation, clean, green energy alternatives and biofuels are very much on everyone’s mind. None more so than Willem Vermaas, professor in the School of Life Sciences and member of The Center of Bioenergy and Photosynthesis. Willem is leading a team of researchers delving into hydrogen production and capturing CO2 to create biodiesel and ethanol with some engineering ingenuity, a tiny cyanobacterium, and a little help from the sun. Welcome, Willem!
Willem Vermaas: Thank you.
Peggy: We hear plenty in the news around the topic of alternative energies. Still, can you tell us what benefits can be gained by going green and some of the different types of systems that are being developed at Arizona State University and elsewhere?
Willem: Arizona is full of solar energy and we’re trying to utilize that to the best of our ability. Unfortunately, Arizona, so far, has not been capitalizing a lot at all on solar energy utilization. Hardly any solar panels on people’s roofs, hardly any other utilizations of the power of the sun. ASU is now starting a fairly large effort to put many more solar panels on roofs of buildings and we are doing our part of utilization of solar energy for direct fuel production. If you have a solar panel, it will give you electricity. It will not give you a very efficient way of transport. For example, batteries can be used in cars, but they are very heavy, very large, not very efficient. Fossil fuels have been the preferred method of fuel for transportation. What if we can utilize solar energy for replacement of fossil fuels? So that’s what we’ve been working on here. And that utilizes the natural process of photosynthesis, where you take solar energy to move the electrons around, essentially. You oxidize water, you make oxygen, you generate electrons so reducing power in order to reuse CO2 from the air, you make sugar out of it. So essentially, you’re converting solar energy to chemical energy. And if we have a way to make chemical energy but make very precise and useful ways of generating molecules that represented chemical energy in ways that you could use if for transportation, then we have it made.
Peggy: What makes biodiesel, for example, a better energy alternative than diesel?
Willem: They would be the same in terms of their chemical composition. Just the diesel is something that came from oil, which was a fossil fuel, was a product from photosynthesis a long time ago. And biodiesel is a product of photosynthesis here and now. So it’s essentially the same process, the same product. One that happened in the past, the other that happens now.
Peggy: When we talk about developing alternative energies, are we talking about a complete elimination of existing coal and petroleum based systems, or a better marriage of old and new technologies?
Willem: I think that the main interest in biofuels right now is not necessarily because of a shortage of fossil fuels. We have coal galore, still for fifty to a hundred years worth of coal. But really the issue is A) how much environmental damage will we generate by extracting coal and B) what will be the consequences of gradually increasing CO2 concentrations in the atmosphere.
Peggy: So climate change?
Willem: Global warming, [Peggy agrees] climate change. It is unclear at this point to which extent CO2 is the main culprit or whether it might be other compounds. But yeah, CO2 is definitely something that we can influence and we don’t want to be in the situation that suddenly we realize that we got into a big deep hole and we can’t get out of it. It’s better to not get too deep into the hole and try to remedy a situation before it develops into something irreversible that not only influences us but also our children and all of nature essentially.
Peggy: So the idea then is not necessarily to replace existing systems. Or is it?
Willem: It will be a gradual process. It is like turning a big, huge, mammoth tanker. That doesn’t happen overnight. Changing our energy economy is not going to happen overnight. So one thing we have to do is make sure that we get the best methodologies and technologies in place to be able to have alternate fuels available over time. And just like computer developments, for example, didn’t happen right away, this isn’t going to happen right away either. At the time that the first Xerox machine was invented, they had a hard time convincing anybody that it would be of any use. [Peggy chuckles]
Willem: Now we all see...
Peggy: It’s ubiquitous.
Willem: As a thing, that’s yeah, that you couldn’t do without. Computers are the same way. Bioenergy probably will be going a similar route. Right now, it’s not going to be a full scale replacement for oil. It won’t be in the next five years either, probably. But certainly over time, the efficiencies will get better. It will be scaled up more and there is no reason why biofuels can’t become a major and efficient and economic replacement for fossil fuels.
Peggy: You’re leading a team supported by British Petroleum, also known as BP, and creating a really unusual system of biofuels production, at least I think so. First, tell us about your quite literally green partner in this work, the cyanobacterium. What is it and where might it typically be found in nature?
Willem: Cyanobacteria are small photosynthetic organisms that are present virtually everywhere. They are a major component of the ocean biosphere. They fix much of the CO2 in the oceans. 30% to 50%, depending on the source, of the total fixation in the ocean. Cyanobacterium are in lakes, etc, are also a major source of aquatic CO2 fixation and photosynthesis. On land even you will find them. They’re part of lichens in some cases, coast to coast. These are a sign of bacteria as well. There will also be green or blue green mats in some places. These are cyanobactertia as well. They are supposed to have been the organisms that were the main players in converting the anaerobic atmosphere of the olden days into the aerobic atmosphere of a few billion years ago. The cyanobacteria were the first photosynthetic organisms that were able to split water, and then they generated oxygen as a byproduct essentially. And that oxygen is what originally first was used for oxidation of, for example, iron. Then it came into the atmosphere and then everything else had to scramble to minimize the toxic effects of oxygen. So cyanobacteria are essentially a ’grand daddy’ of plants, in the most literal sense. It is presumed that cyanobacteria are the progenitor of chloroplasts that at one point, in the distant past, a cyanobacterium invaded a eukaryotic cell, the cyanobacterium gave up its independence, most of its genetic material went to the nucleus and you ended up with a chloroplast, which you now see everywhere in plants.
Peggy: Are these features about cyanobacteria what made them of interest to scientists initially?
Willem: Well possibly, but at that time much of what I just told you about cyanobacteria wasn’t known yet. This is one of those cases where scientists are interested in the world around them, and in the process, you develop and you discover all those pieces of new knowledge.
Peggy: So how and why did you start working with this organism?
Willem: Well I was interested in photosynthesis and understanding what all the different proteins were doing in that process. It’s essentially a whole long line of enzymes that together are forming a bit of a ’bucket brigade’, in terms of splitting water, in terms of reducing CO2, and making sugars. And the real question 20 years ago was what proteins are all involved? Where are they found? How do they interact? And what are all their components? And this was a good system because it’s simple, it is evolutionary ancient and it had the potential to be genetic code for the proteins. And if you want to, for example, remove a protein, you do that by removing a gene.
Peggy: So what makes it ideal for genetic engineering?
Willem: Back in the late 70’s, a group in Moscow, of all places, discovered that a group of cyanobacteria, including the one that we’re working with now, can take up DNA spontaneously. And then after the DNA has been taken up, the organism can integrate it into its own genome making it part of its own genetic information. So in a sense, this was a natural system that was directly applicable to molecular genetics and genetic modification. The basis for making changes in a very directed matter in the genetic makeup (i.e., the number of proteins that they could make) was already there, and that was there just for us to utilize. And that then led to an interest of a Japanese group in the 90’s to take the DNA and determine its full sequence. And it was the first photosynthetic organism that had its sequence determined, and that was the fourth or so bacterium in the world that had a known sequence. It was even before Escherichia coli, which is the mainstay for bacterial physiology work.
Peggy: How would your solar cyanobacteria biofuels system work? And what advantages does it have over some other types of biofuels production, like agricultural food crops, for example?
Willem: Well I would think that the main advantage over food crops is that our system is much more efficient, in terms of conversion of light energy into biofuels. It depends a little bit on what you compare it to with regard to the higher plants. But even with the best systems of higher plants for biofuels production which would be palm oil or the palm tree essentially our system is at least 10 fold, and according to some 50 fold better in terms of the efficiency of conversion. One of the main reasons why this system is so much more efficient is the fact that you can provide it easily with CO2. The other reason is that this organism doesn’t need to synthesize all the other plant parts, just a little cell, and it doesn’t need to make anything that isn’t its own.
Peggy: So no roots and no stems and no limbs.
Willem: No, nothing. Nothing to support it. It’s a very efficient system. Also it can grow essentially year long, so you don’t need to worry about limited coverage of leaves in some parts of the year, and too much coverage other parts of the year. So you can optimize it to be efficient all year long. So that is one part, a much higher efficiency. The other part is that at least here, in a relatively arid part of the world, we have much land available, fairly limited water resources, and lots of sunshine. And in this kind of place what we can do is have a relatively large area of land committed for biofuel production that does not compete with any food production. Whereas in most of the other parts of the United States, at least, corn now is being utilized both for feed and food, as well as for biofuel production.
Peggy: I also read that your system would eliminate the use of extra nitrogen?
Willem: Yes. In plants, you know how much nitrogen you put in the soil, but you also know that the rain comes and will wash out most of the nitrogen that you have applied. In an enclosed system, you have much better control over the amount of nitrogen that you put in and it can’t go anywhere, except in cyanobacterial cell products. And also, you’re able to utilize, for example, groundwater, which at least in certain areas of this state is contaminated with fairly high levels of nitrate and nitrite. So you can essentially take that fixed nitrogen and utilize it for growing cyanobacteria. So you can essentially do a bit of bio remediation of the water at the same time.
Peggy: How do you genetically modify the cyanobacteria to make them ideal for your system?
Willem: Part of it is by trial and error. You are trying to produce a system where you rate limiting steps for, in this case, fatty acids production have been removed. We’re taking out one rate limiting step to go make something else rate limiting. And so you have to take it one step at a time. It is fairly easy to, for example, overproduce native genes, introduce other genes from other systems, remove genes that are for competing pathways that are nice for the cyanobacterium to have but not needed for biofuels production, etc. What is hard is to predict what exactly the outcome functionally will be of a gene that you put in. You know exactly the gene you put in; you can predict the levels at which it will be expressed. How exactly it will improve your fatty acid production remains to be seen. So it is a matter of experimenting, it’s a matter of using all the bits and pieces of information available and making your best guesses and just try out a lot of different things. Many of them will work, some of them won’t.
Peggy: [laughs]
Willem: And that is science.
Peggy: Who are your other partners in this work with BP and how did your collaborations come about?
Willem: The main partner in this work is Bruce Rittmann who is at the Center for Environmental Biotechnology here at ASU. He is a civil and environmental engineer. I can take it up to the level where we design an organism that is good at making extra lipids, for example. What I’m not good at is scaling up, and that’s where engineers come in very handy.
Peggy: [laughs]
Willem: And at the Rittmann Group and various others in the Biodesign Institute, they utilize their best engineering knowledge to come up with an energy efficient system of growing cyanobacteria. There is a very large history, going back 25 years, of growing algae, for example in large ponds. But there they didn’t have to worry about the amount of energy it took them to pump the algae around, to do the harvesting, etc. And also those were open ponds initially, and in Arizona that’s not a good system because you don’t want to evaporate that much water. So for the design of those photo bioreactors, as they’re called, there is a lot of de novo engineering that needs to be thought about and that’s in very good hands with Bruce and his collaborators.
Peggy: How did you meet Bruce?
Willem: He was well known in these circles and I mentioned to him, “Hey, I’ve been thinking of that and I really need to have an engineering partner.” And Bruce is sufficiently close to a biologist that there isn’t a big canyon in ween our language and our expertise.
Peggy: Now I understand that the two of you have put together a prototype?
Willem: Yes, there is a prototype that is being built. It should be ready in May or June of this year on top of one of the buildings here on campus. And the idea of having a prototype bioreactor is that it’s hard to predict based from laboratory scale work on how things will work in a much bigger reactor. It’s hard to harvest you can’t just spin things down in a centrifuge, you have to find creative ways to harvest the cells, you have to find good ways of drying, you have to find good ways of extracting. And not just extracting, but extracting in a green fashion so that you don’t use all kinds of organic solvents in large amounts, etc. So there is quite a few chemical engineering issues that need to be looked at and that’s what one of those pilot operations will be good for.
Peggy: You’ve pointed out that your biofuels system can tap into CO2 waste coming from a power plant. Is this system dependent on these older, basically dirtier, technologies, or can it stand alone?
Willem: It is good to have a high CO2 concentration in the water because, the more CO2 you have available, the more CO2 can be fixed by the cyanobacteria. It is easy to have CO2 concentration become the rate limiting step for synthetic productivity. Eventually, it should be feasible to have CO2 be taken up in the fashion that we don’t depend on higher concentrations of CO2 in the medium, but that’s yet another engineering step. Right now it is simpler to just have a CO2 supply right next door. It’s also good for power companies to say, “Well, we generate CO2 but see what we do with this CO2 it goes back into generating biofuels.” And if you look around at good graded land around the valley, power companies are a good source of that land. So if we can work that out, then it is to everybody’s advantage.
Peggy: So it’s a great partnership, and good in this way that you’ve said that things would be transitional. So building your types of plants, if they can be scaled up next to power plants means that the power plant’s cleaner, that you have this extra source of fuel. And then, when the day comes that it’s a standalone process, it’s an easy transition and everyone benefits.
Willem: That’s correct.
Peggy: Can you go wrong developing green technology?
Willem: You can, because of the fact that green technology is not always green. You have all shades of green and what can be green from one perspective can be not so green from a different perspective. For example, some people argued that bioethanol really isn’t as green as it sounds because of the relatively high energy demands in the process of making ethanol, in terms of transportation of materials and the ethanol. So some people argued that there really isn’t much energy gain or green energy gain from bioethanol production. I think it is important, an example of how you have to look at all parts of the equation when it comes to bioenergy production and how green this bioenergy actually is. People have to take into account, for example, the ecological ramifications of making the materials you need. For example, photovoltaics, because the fact that it depends on minerals that are not necessarily all that abundant have not necessarily a green connotation. In Australia there are areas of the land that are all dug up because of photovoltaic solar cell production. By the same token, we have to look into the amount of materials needed for, for example, harvesting. People have argued as well that it takes so much energy to make fertilizer that even if some of the bioethanol issues get resolved, you still aren’t out of the woods because of the fact that you need a lot of energy to grow the agricultural material to make biofuels from. We don’t have that problem in our system. We have looked at the cyanobacterial system from all different perspectives, of how much energy do you need to pump them around, how much energy do you need to harvest, how much energy do you need to make the pipes to house them, and so far so good. It all looks like a very favorable energy balance.
Peggy: I’d like to shift gears for just a little bit and talk about another line of research that you are pursuing with support from the ASU president’s Intellectual Fusion Investment Fund. This second project also centers on utilizing cyanobacteria for energy/hydrogen production. Tell us a little about your work there.
Willem: This is looking from a perspective of what are the best fuels that we can have looking beyond just oil. Hydrogen can be viewed to be the cleanest fuel around, because of the fact that when you burn hydrogen, you just get water. You can’t really beat that. But on the other hand hydrogen is also known for its rather explosive properties in the presence of oxygen. So you have to be relatively careful. None the less, hydrogen is a very attractive fuel for certain applications. And, naturally hydrogen can be made by a variety of microorganisms including cyanobacteria. The enzyme involved in hydrogen formation is however a very oxygen sensitive enzyme, hydrogenase. If it has oxygen present hydrogenase is not active and you will not form hydrogen in an environment where you make oxygen. And as you now, Photosynthesis will generate oxygen. So we have a slight problem.
Peggy: [laughter] A little bit of a conundrum there.
Willem: Right. So what we need to do is find a hydrogenise that is active in the presence of oxygen. And we have to realize that we understand only a very small part of the microbial world. Only a few percent of the microbes can be cultured some place and therefore are reasonably well known, and all the rest of it is just a big unknown. It is likely that somewhere in that unknown wealth of information there is a gene for hydrogenase that is totally able to function in the presence of oxygen. And Ferran Garcia Pichel here in the School of Life Sciences is the person who is going to look at hydrogenase in desert environments in organism that we might or might not be able to culture well. The other thing that we are looking into is to temporarily separate hydrogen production from oxygen production, either in two different cells or during two different times of the day.
Peggy: So two very serous engineering issues one with the bacteria itself and perhaps in the system itself. Are we talking about near term application for either of these two systems?
Willem: The hydrogen economy itself will be a long ways off. Iceland is furthest along, they are trying to be independent from any fossil fuels in the not so distant future and they are trying to have hydrogen be one of their transportation fuels of choice. But for the rest of the world I think the hydrogen economy will be a long ways off. So we have a little bit of time here. It is not only that right now we don’t have a good system to make a lot of hydrogen very cost effectively, but even if we have it their wouldn’t be a good system to distribute and to use it. So we have a little bit of extra time for our relatively advanced metabolic engineering to make this all work properly and with decent efficiency.
Peggy: Now you have been working with cyanobacteria and genetic engineering for almost twenty years. What technologies or discoveries have occurred over the last two decades that have made it possible to envision energy systems based on these organisms?
Willem: I don’t think that there has been any specific new development that has been extremely critical. The genome sequence, that of course is something that you must have in order to be able to do metabolic engineering because you need to know what the genetic make up of the organism is, what the pathways are that they can use, what you need to put in, etc. So I think that if anything, the genetic information of the organism has been the major issue. However, I should point out that twenty years ago Mel Summerfeld was here at ASU and is still here on the Polytechnic campus. He has been working in this general field for several decades. Back in the seventies he was already fishing for algae that were able to make oil droplets and he is still continuing that work in a variety of different ways. So, back twenty years ago that work was feasible and was being done. And now, the new spin that we have is that we can help Mother Nature to develop a system that is much more efficient in biofuel production. So in essence the whole field of molecular biology and all the tools that have been developed both in our lab for Synecocystis as well as elsewhere, those all are key for making this metabolic engineering project feasible.
Peggy: When did you first know you wanted to be a scientist?
Willem: I still don’t know if I want to be a scientist...
Peggy: [laughter]
Willem: But I am one. I think it is curiosity, who feels that there is much out there that is not yet explored. And much that we may be able to utilize, and much that we may be able to harness. I think why I am doing the kinds of things that I am doing is maybe not necessarily and intrinsic interest in science but an intrinsic interest in education, as well as some kind of a social awareness and trying to help in my own little way solve a few of the major issues that we have gotten ourselves into.
Peggy: Well, Willem, I want to thank you very much for being with us here today and showing how discovering about out natural world and developing understanding even about the tiniest creatures around us and an investment in creative thinking can lead to revolutionary technologies and hopefully greener living.
Willem: Thank You.
Peggy: To learn more about research by Willem Vernaas and other novel technologies being pursued at ASU go to sols.asu.edu, ASU Alumni Magazine or ASU Research Magazine or their website at researchmag.asu.edu. This is Peggy Coulombe and you have been listening to Science Studio. Science Studio audiocast is recorded in our own KSOLS Grassroots Studio in the School of Life Sciences. Our theme music comes from the website “Magnatunes” and was composed by Yongen, School of Life Sciences and the College of Liberal Arts and Sciences on the Tempe campus of Arizona State University.
Transcription by CastingWords