Interview with Dr. Paul Dauenhauer: Sustainable Manufacturing in a Hungry World
Sustainability is in demand. A 2021 survey from Oxford Economics found that 65% of companies are taking steps to improve manufacturing sustainability, and 50% are greening their supply chains. This has led to a renewed interest in biomaterials as a chemical and fuel feedstock.
But what effect would a biomaterials-based chemical industry have on world hunger? It’s feasible that diverting crops or farmland for the purpose of feedstocks for the chemical industry could increase food prices. With 690 million people without enough food to eat (United Nations), and the increasing effects of global warming, there are concerns that sustainable manufacturing techniques could further compromise food security.
One person navigating this rocky terrain is chemical engineering professor, entrepreneur, and MacArthur Fellow, Dr. Paul Dauenhauer. His expertise in catalysis has allowed him to have a significant impact on sustainable manufacturing, and carbon capture. We talked to him about the intersection of biorefining, food security, and climate change.
Dr. Dauenhauer will be presenting at the “Zero Hunger Summit,” organized by the American Chemical Society. This free online conference, taking place December 5-8 (11 AM -1 PM EST), will explore how chemistry and engineering can contribute to the U.N. Sustainable Development Goal of “Zero Hunger.” Register for the Zero Hunger Summit.
This interview was edited for clarity and brevity.
Climate change is probably the greatest threat to long-term food security. One of your research areas is carbon capture, a critical technology for avoiding global warming. How are you trying to manage atmospheric carbon?
One of the goals, of course, is to make carbon-free or carbon-neutral technologies to produce energy. But that's not going to be enough. Even if we were able to switch right now - implement all of these low carbon technologies - we still have the problem that there's a lot of CO2 in the air that we don't want to be there.
Now, what's the best way to get CO2 out of the air? If your technology requires too much energy, you might as well just use your renewable energy to offset fossil fuels. You need low-energy, low-cost processes to take CO2 out of the air.
What are those? The one that makes the most sense, technically and economically, is to let trees and biomass do all the accumulation of CO2 in the air for you. There is a huge entropy penalty when accumulating all of that CO2. But trees do that for you for free.
The problem with the tree, of course, is that once you cut it down, you can't just bury it because it'll degrade into CO2 and methane. Instead, what we do is take trees and grasses and we torrify them. That means we heat it at moderate temperatures (300 oC), and it turns into a black char that's chemically stable for tens of thousands of years underground. You put that under about two feet of soil, and it'll stay there practically forever.
We joke that this is essentially the reverse coal process. We're putting the carbon back in the ground in a way that's permanent.
There are concerns, though, that biomass-based carbon capture methods may cause competition over arable land, leading to increases in food prices. Do you think this can be avoided?
Once you dig a little bit deeper, you see this is not a major issue because the biomass we're talking about is not going to be growing where food is growing. The biomass we're talking about is waste material. It could be waste paper or agricultural residues. It can also be grown in places you wouldn't grow food, like forests or non-arable land.
Another theme of your research is the production of chemicals from biomass, such as surfactants, xylene, and isoprene. What is your group working on these days?
We're still looking at the biggest chemicals that are important for the chemical materials industry. A lot of this is surfactants because they are a very important class of chemical, both in terms of sustainability and volume, and because they go down the drain.
We are also working on monomers. Caprolactones are interesting because they can be derived from biomass at low cost and can go into biodegradable polymers that have better properties than the conventional polymers we make from fossil fuels.
There are also concerns that manufacturing chemicals from biomass could end up worsening world hunger because agricultural land is used for chemical feedstocks rather than food. Do you think it is possible to design economically viable biorefineries without competition with food systems?
Absolutely. There are at least two elements. Number one is to look at the scale of chemicals compared to food or even energy. They're on completely different scales.
Also, the goal is ultimately to get to use materials that we wouldn't use for food anyway. We wouldn't compete with food in that sense. Put both of those together, and I don't see it as a big challenge.
Where this becomes a problem is when we talk about using corn to make ethanol. There are many other factors. If we switched to a lower meat diet, that will also drive food prices down because we're using a lot less corn to feed cattle.
Several companies have been spun off from your research. What role do you think the private sector plays in developing and deploying technologies that can address world hunger?
It's a very important role. If we develop technology at a university, we're not legally, structurally, or personnel-wise in a position to take that technology to a point where it can actually manufacture something. The private sector is absolutely critical in accumulating the capital, putting together the manufacturing capability, assembling the team, assembling the legal structure, everything you need to be able to get these technologies into the marketplace…
Universities in the past 10-20 years have invested heavily in these approaches to getting technology translated out of the laboratory into companies where they can actually have an impact. The University of Minnesota has really put this into hyperdrive in the past ten years. I think last year we started 22 companies.
In December, you will participate in the Zero Hunger Summit, which is part of the ACS's campaign for a sustainable future. This online conference is organized to explore the role of chemistry in sustainable agriculture and food security. What are you hoping to come from this event?
These systems are all integrated together. We're talking about energy, food, the economy, jobs, education, the legal system. They're all incorporated together, and they all interact with each other. I am hoping to find where the intersections are, where the challenges are, how they affect each other, and how we can make a real impact.
People in the political world, the legal world, and the academic world, we have to decide what we are going to do. We have to make decisions from our point of view, and we don't always know how that will affect other areas that aren't our expertise. Getting people together to talk about these things helps us constantly re-evaluate and imagine what it makes sense for us to be doing every day.