Environmental Solutions that make Economic Sense: Q&A with Korneel Rabaey
The 2025 iSEE Congress, “A Circular Bioeconomy as a Path to Net-Zero” is fast approaching! Scheduled to take place September 25-26, 2025, this free public event will feature panel discussions on sustainable food, biofuels, plastics, and carbon reduction strategies from academic and industry research experts, including a keynote address from Korneel Rabaey.
Rabaey is professor in the Department of Biotechnology at Ghent University, as well as honorary professor at The University of Queensland. He is one of the founders and the present Chief Technology Officer of CAPTURE, a center focusing on resource recovery in the fields of Water, Carbon Capture and Utilization and Plastics to Resource. In addition, he is also the founder of HYDROHM, a company focusing on electrification in the water sector. His main research efforts focus on resource recovery from wastewater and CO₂ streams from industry.
iSEE Communications Intern Anjali Yedavalli spoke with Rabaey about his research and the future of a circular bioeconomy. This interview has been edited for length and clarity.
Our Congress theme this year is a “circular bioeconomy,” which is a new term for many people. How would you define this term, and why do you feel it’s an important and timely topic right now?
“Circular bioeconomy” is a term that refers to a biomass- and bioconversion-based economy where we can use microorganisms to supply our products, and also to recover resources. It’s extremely broad, from setting up a way for the wastewater treatment plant to recover phosphorus, to taking waste biomass and making new polymers. We call it a “bioeconomy” because it’s not just a set of processes; it’s a contributor to the economy at large. And increasingly, you see that these biomass- and bioconversion-based processes make a lot of economic sense.
You say the term itself is broad. What specific parts of it are causing a lot of buzz or excitement?
I think there’s currently a lot of interest in finding novel, more sustainable approaches to supply food. Sustainably and economically producing protein plays a key role in that.
And a second large theme that people are excited about is bioplastics, including bio-based plastics, and biodegradable plastics. On the one hand, of course, there are issues caused by waste plastics in the environment. On the other hand, there is a necessity to make a supply of novel plastics more sustainable.
Why should policymakers, economists, and scientists be interested in a circular bioeconomy?
From a policymaker perspective, there’s a big need to update our regulatory frameworks. One of the issues in our current frameworks is that many resources are considered waste. And if you produce something from waste, the legislation says that the product is also waste. You can make the nicest plastic from waste biomass, and it’s technically still classified as waste. Working on these so-called end-of-waste regulations is critical.
And more generally, the bio-based economy is noteworthy because it interacts with supply chains. One of the reasons we are producing novel forms of protein is that, for example, if you have to feed salmon for our consumption, about half of what you feed to salmon is wild caught fish. They just grind it up and provide it as a so-called fish meal. And so we are depleting stocks in the ocean by catching fish that will be fed to other fish. Perhaps instead, we could produce novel sources of protein to feed the salmon. But, you need to optimize these technologies and strategies so they can be economically viable.
One of the aspects of a circular bioeconomy that you study is resource recovery. What does this term refer to?
Resource recovery refers to the way we recover something from a source that is considered “waste.” And the simplest example is recovering water from wastewater. Wastewater is about 99.5% water and 0.5% of a not-so-nice thing. So recovering the water is a massive resource that you can get back.
What emerging challenges or opportunities do you see shaping your field in the next 5 to 10 years?
In terms of general opportunities, I think we’re at a phase where, in the next 5 to 10 years, we want to put into practice the technologies and methodologies we’ve been researching so far. But to do that, we really need to think of the societal transition necessary to implement a bio-based economy. In order to have a societal transition, having the technology is only one of the necessary ingredients.
People will wonder, “Is it economic? Is it better for the environment? Is it socially acceptable?” These are very important questions. We need to inform people about bioproducts and find ways to get their buy-in. And this is a difficult task.
I’ll give an example in the context of microbial proteins. So we’re specialized in “side streams,” which are the leftover materials generated during food processing that are not the primary product. We grow organisms on these side streams, and they’re very protein-rich. You can use this protein to help supplement human nutrition. And you might say, “Let’s just make hamburgers from this microbial protein.” However, in my opinion, that’s a bad idea. Hamburgers made from microbial protein will be new and different, and many people will be hesitant to accept them.
How do you get the rest of the population on board? Well, microbial protein has great environmental benefits – it saves an enormous amount of water and greenhouse gas emissions. So you might propose, “If I replace 10% of that beef hamburger you’re eating with this microbial protein, you will not taste or see the difference, but we’ve made 10% of it more sustainable.” These approaches make it a lot easier to reach that societal transition and acceptance.
What do you hope attendees take away from your upcoming keynote address at the iSEE Congress?
My keynote will emphasize that microbial protein can be produced from carbon dioxide derived building blocks, allowing for high volumes of protein production, which would be very economical. The use of this protein is not limited to food or feed; it is also an attractive option for producing plastics.
What advice would you give to students who want to follow a similar path or make an impact in your field?
Dare to think far ahead to determine which process or technology will make a true difference, and do this based on calculations that don’t start from the premise that everything will be very cheap in the future. It won’t be. Then determine what you can contribute along this path and who you need to work with.
I work now partially at a university and partially in two startup companies. But before doing a Ph.D. and further studying, I had a lot of doubts about what I was doing and where I was going. Whatever decision you make, you cannot turn it back, but you can change what you’re doing in the present. If you find you’re not doing what you like, then do something else.