by David Schwartz
Dr. B. Greg Mitchell is a research biologist and senior lecturer at the University of California San Diego, Scripps Institution of Oceanography. An avid surfer, Greg credits the gnarly waves of Black’s Beach in La Jolla for his decision to become a marine biologist at Scripps, a place where he could literally surf the ocean in the morning and study it under the microscope in the afternoon.
In 1987 Greg received his PhD in Biological Oceanography from the University of Southern California, with a focus on the physiological ecology of algae as related to absorption, fluorescence and aquatic optics. NASA, the Office of Naval Research, the National Science Foundation, DOE, and the National Oceanic and Atmospheric Administration have sponsored his research on phytoplankton photosynthesis and growth models, aquatic ecology, ocean optics, and satellite remote sensing.
For more than two decades Greg has promoted mass culture of algae to mitigate CO2 and wastewater nutrient loading, as well as to create biomass for fuel and animal feed. “There’s science and there’s advocacy. I’d been a little more of an advocate for a couple of decades,” he says. “So in 2004 I said I’m going to get more scientifically involved in algae, and by 2007 I mapped myself into this community and got involved with creating the program for the first Algal Biomass Summit, which was held in San Francisco in 2007. I helped establish that annual meeting and got on the steering committee for creating the Algal Biomass Organization in the spring of 2008.”
Also in 2007 Greg worked with Dr. Stephen Mayfield, who was at Scripps Research Institute at the time, to convince the University of California San Diego to establish a regional center of excellence for collaboration in algal biotechnology research and development. The original ad hoc collaboration among UCSD faculty and other San Diego collaborators eventually became the San Diego Center for Algae Biotechnology (SD-CAB). UCSD recruited Dr. Mayfield to join the faculty and lead SD-CAB as the Director.
Greg’s applied research currently focuses on optimization of yields of bioenergy molecules in the light-temperature-nutrient matrix that regulates algae growth. He also works on numerical modeling for optimizing algae yield, and the design of closed and open photobioreactors to optimize yields.
We recently met with Greg on a tour of the Scripps Institution of Oceanography in San Diego, a city that takes algae and clean energy so seriously that it’s now practically their claim to fame. We talked about his algal adventures and, at a higher level, how the ocean holds the keys to our future.
Tell us about some of your current work with algae.
My work is primarily focused on evaluating the performance of any algal strain within the growth limitation framework of light, temperature, nutrients, CO2 and salinity. You have a biological organism that grows within what I call an abiotic, or a physical-chemical matrix of regulation. So if you’re at the freezing point of water and you have ice forming, you might think, nothing is going to grow there. But I’ve published research on algae that will grow at the freezing point of water and they can double their biomass in three days.
The point is, each algal strain has it’s unique growth performance within the broader physical-chemical matrix that regulates growth, whether it’s salinity, temperature, light, pH, CO2 delivery, nutrients—all these environmental factors play a role. My work looks at the performance of individual organisms within that matrix and their ability to adapt physiologically.
To put it simply, I evaluate the growth performance and the yield of biochemicals of interest as regulated by non-biological factors such as light, temperature and nutrients. I’m what you call an eco-physiologist. I study the physiology of the organisms within the context of their local ecology, whether that’s a laboratory system, a pond, a lake, or an ocean.
What algal strains do you find to be optimal for oil production, and under what conditions are they optimized?
I have not been doing a broad survey of many strains. I don’t have the staff to do that. I have done some work that was specifically requested by General Atomics on proprietary organisms of interest to them. In the last year and a half or so I’ve had a contract with them as part of their Advanced Research Projects Administration (DARPA) regarding algae for jet fuel. I can’t say much about that, but we take their strains into our lab and characterize certain aspects, like pH performance—really not much different than what virtually everyone’s doing—growing the biomass of the algae and putting it into a nutrient-limited phase that enhances the oil formation.
It’s a two-step process that people are looking at—the rapid growth phase and then the oil formation phase—and I’ve been working more on the rapid growth phase: for example, what is the growth performance of a particular algal strain at various ranges of pH? Any of these experiments takes a couple of months, and since we don’t have that many people in our labs, we work more on the concepts with a few model organisms, as opposed to exploring thousands of organisms.
Phytoplankton consists of several types of microorganisms, including green algae, cyanobacteria and diatoms. In your research of these, what are some of the conclusions you’ve reached with respect to their application to oil production and their extraction capabilities?
I think that everything is on the table right now. We’re too early in the applied biotechnology of algae and cyanobacteria to choose winners. While many organisms are found to be difficult to extract, it’s almost guaranteed that we are eventually going to find something like an algacidal bacteria that produces an exoprotease that can dissolve the cell wall of algae x, y or z. We just haven’t found that bacterium yet.
But it’s not going to be all about algae, it’s going to be about the algae and the whole system downstream to deal with it, and upstream and in the ponds. So, in the end, we’re going to be looking at more than the algae. We’re going to be looking at the ecology of the system.
When you consider the way algae were formed, first of all there were cyanobacteria that photosynthesized, and there were some organisms that would eat them. And something that ate a cyanobacterium decided that if the cyanobacterium could produce sugars for them, they wouldn’t digest them. So the cyanobacterium ended up becoming internalized in an organism that would then replicate both its primary original animal part and its plant part.
The cyanobacteria are prokaryotes, and the green algae and higher plants are eukaryotes. The eukaryotes are more related to us than they are to cyanobacteria. And the terrestrial plants are more related to us than to the bacterium. So, what happened were the chloroplasts in higher plants and green algae originated as bacteria, and that happened more than one time, creating different strains of progenitor algae. And then some of those algae that were eukaryotic, as opposed to prokaryotic bacteria, got re-ingested into something else again.
So you had multiple sets of complex genes being mixed, not through simple concepts of Darwinian evolution with mutation giving some sort of advantage, but massive lateral gene transfer of entire genomes into new organisms.
Because algae have that vast diversity, I expect that as we domesticate algae we’re going to find way more opportunity for industrial biotechnology from all the different biochemicals we can get out of algae than we can out of terrestrial plants—because of this massive amount of evolutionary diversity which should reflect both genetic and biochemical diversity. That’s an untapped theoretical concept, which should be a fundamental driver for why we invest in more discovery in algae over the coming decades.
It seems that most of the research is being done at the microalgae level. Do you have a strong feeling about macroalgae as a biofuel source?
We had a seaweed—macroalgae—project that was funded by DOE NETL last year, and I think that you can’t rule out macroalgae for a whole variety of reasons. It may turn out that harvesting macroalgae is going to be far simpler and less expensive than microalgae, which might mean that we can spend more money on the production system. The goal eventually is going to be to minimize the cost across the entire value chain so that we can make it economically viable. So I think there is merit in exploring both.
I think if you look at the current algae industry, you’ll find that there’s a much larger macroalgae industry than microalgae by probably at least a hundred times. There’s a large seaweed industry for food in Asia. There’s a large seaweed harvesting industry for all sorts of chemicals, emulsifiers, alginates in ice creams, lipsticks and makeup…all sorts of things coming from seaweeds.
A lot of people say microalgae grow much faster than macroalgae, and generally that’s true. But the biomass yield is the product of the growth rate times the density, and macroalgae typically have denser biomass than microalgae. Microalgae are generally pretty low density in water, and macroalgae might grow slower but have higher density, so you’re going to be trading things off. Now macroalgae typically create more starch or other carbohydrate energy storage, rather than oils. Some macroalgae do store oil, though not as much. But maybe through domestication we might be able to bring oil forming traits out.
There are several good reasons why microalgae are being more explored. I like the model of a fluid system that you can manage in an automated way, like in a refinery or chemical process engineering, where you’re dealing with a fluid that you can pump. Microalgae lend themselves to that, everything just flows. With macroalgae you have to structure a system for growth and harvesting that’s not fluid flow.
Much of your research seems to focus on phytoplankton activities in the Arctic and Antarctic regions. What is the potential for developing algal oil from these regions?
I think that for the most part we are going to be domesticating algae from regions that are warmer and have more stable temperature and light climate. This would be plus or minus twenty or thirty degrees of latitude where we’ve got lots of sunshine. Having said that, there are some very interesting things in algae commercialization that may come out of the polar regions, from algal strains that can only live in cold temperatures.
For example, industrial enzymes are one domain of algal biotechnology that has high value. It’s not a commodity like oil, and I think in general we have to be careful about looking at algae as only something that’s going to be used for fuel, because I expect at least half of the economic value is going to come from other things, especially animal feed.
In all these regions, especially with macroalgae, as we gear up harvesting more and more, how does it relate to the ecosystems? Do you see any threat as we look at harvesting large quantities of macroalgae from the oceans?
I think that is an issue. I would like to envision humans moving upstream and taking our waste nutrients and waste CO2 and engineer systems to produce the biomass we need on a smaller amount of land and with less water than we do with terrestrial crops. Anything that is indiscriminant harvesting of natural ecosystems I think threatens natural ecosystems and we have to be very careful about how we proceed.
What observations do you have about the entrepreneurs racing to develop algal biofuels—what are they seeing and what are they missing?
I think they’re seeing that it’s more challenging than they thought. When you read the Aquatic Species Program Closeout Report from 1998 and it says something like it is achievable to make algae at $75 a barrel of oil, maybe that’s $120 a barrel in today’s terms. At the time of the project, oil was $10-$15 a barrel, maybe equivalent to $20 or $30 now. But it’s more difficult than a straight up economic equation. So I think that’s what they’re seeing, that there’s difficulty finding strains, maintaining the strains, dealing with invasives, and I think a lot of entrepreneurs have gone down that road because of their visions of algal biofuels.
I think that people are starting to realize that the co-products are maybe the dominant economic driver, and a lot of that came out this year at the Algal Biomass Summit where people were looking, many for the first time, at animal feed co-products. That was always true, though people were chasing the fuel side of it and weren’t paying as much attention to the other products early on. But it’s one of the reasons why I, and others, fought hard that the Algal Biomass Organization was Algal “Biomass” and not the Algal “Biofuel” Organization. We actually had to battle a few people on that one. We laid out some fundamentals, and showed that you’re going to get to fuel by going through feed. Some people might go straight to fuel — I’m not saying it’s impossible, but I wish them the best of luck.
Right now we’re destroying the global marine ecosystems by netting every possible fish, regardless of its quality for the human market. We’re grinding them up, turning them into fishmeal, and selling them for pig and chicken food and into the aquaculture business. My vision for the future is that we are going to feed animals with algae, and that’s why the Algal Biomass Organization should not be narrowly focused on fuel and energy, but also on replacing traditional animal feeds with algae. Imagine: vegan salmon, pig or chicken meal made 100% from algae!
The question that always comes up is when? What kind of timeframe, or development increments, do you see for the logical scale-up from lab to scaled production of algal biofuels?
I think the reasonable cost basis is that it will take some time if we are going to compete with petroleum, and this is where policy comes in. I don’t see climate policy driving things in the near term. And if there’s not a cost for carbon, then that hurts things like algae for biofuel development.
The wholesale market for Spirulina and Chlorella, on the other hand, is around $10,000 a ton. And we need to bring the cost of production down to about $1000 a ton. That’s not going to happen overnight, or from the first 200-acre development. The first couple of hundred acre farms are going to take at least a year to design, and then a year to permit, and a year to build. Now we’re into three to five years just to operate a hundred acres. I don’t see how anything is going to be breaking through economically faster than five years.
And I also don’t think the first few farms are the ones that will end up winning. The first horse out of the gate in the Kentucky Derby doesn’t usually cross the finish line first. My view is that you’re going to have to have multiple things going on that are going to take three to five years to actually roll out, and then operate for a while, and then go to the next larger scale. I’m personally looking at ten years. I think that is realistic, maybe even an optimistic time frame.
That gets me in trouble with some of my friends and colleagues on the business side, but three years ago people were saying algae commercialization would happen in three years. Clearly, it did not happen in three years. So I think we need to get the first several hundred-acre units out there that are pre-commercial pilots, and then we need to roll out the refined versions as demos. I think that then we’ll have enough information, from the industrial engineering and scaling perspective, that we can put it into robust models and show how going to thousands of acres will work. Then the venture capital will flow. Bottom line: we need to invest both publicly and privately, commit to the long term, and be patient.
Do you have any advice to the industry regarding moving forward in the most intelligent way?
My view is that ultimately the biggest benefits of algae are that they produce bioenergy and nutrition molecules far more efficiently in time and space than terrestrial plants. And they can do it in degraded water, saline water, using point sources of CO2, non-arable lands, all these are common knowledge.
The companies, the academics, the government policy people, the NGOS all agree that we need to produce fuels and feed more efficiently with respect to our limited resources. We have to produce photosynthetic biomass, not so much for energy, but for sure we have to produce it for animal feed. Animal feed is about 80% or more of human agriculture, and it consumes about 80% of our use of water, since most water is used for agriculture. So there’s no way the biofuel domain can be encroaching onto the traditional water and land use for feeding animals and humans. I think this is the domain where algae can show their largest value to scale-up.
My feeling is that it’s essential for the industry to play in a collaborative way within this policy-related framework of sustainability and life cycle analysis, and that the industry really needs to come together in the next few years to show that they can cooperate in that area, while they still compete in the development of proprietary organisms, proprietary methodology, proprietary extraction tools, or whatever.
They need to find a way to bring the inputs and outputs that are fundamentally related to sustainability into a common framework that can be translated into robust lifecycle analysis models that can then inform policy. Because, from an economic point of view, the policy makers can’t see it right now. From an energy security perspective, yes, policy makers are interested, but ultimately to get the NGOs and the environmental organizations behind algae, we’re going to have to show that we’re really benefitting the environment with this and get the advocacy, and get the policy. Because if we want society to invest in algae we have to show that it’s superior.
Another thing that’s happening that is quite important is the National Academy of Sciences is being funded by the Department of Energy to do a study of sustainability of algal biofuels in 2011. That report will presumably come out sometime in 2012. I think that the sustainability of algal biofuels is absolutely going to be linked to the integrated lifecycle analysis and its merit to not just greenhouse gases, but to water, to nutrient loading in our watersheds, to arable land, to biodiversity, and so forth. And algae can be very positive in all of those. So, if industry can cooperate well in the coming year and make sure that they inform the process that the Academy will go through in their study, I think that will be beneficial for all of us who want to see algae achieve our expectations.