Bruce Rittmann in the lab with researchers

Focusing on the little things: Rittmann discusses his work with microorganisms

In honor of June 5 being World Environment Day, we are featuring Bruce Rittmann, director of the Biodesign Swette Center for Environmental Biotechnology and his work focusing on how microorganisms impact humans from our water to our metabolic health and beyond.

Microorganisms are key members of the staff at the Biodesign Swette Center for Environmental Biotechnology. Through forming partnerships with them, Bruce Rittmann and his team aim to remove pollutants in water and create renewable energy. Having worked with the Biodesign Institute for nearly two decades, Rittmann has played a dominant role in successful projects and discoveries. He is internationally recognized as a leader in managing microbial communities, and he also invented the membrane biofilm reactor for which he holds 11 patents. 

Photo by Andy DeLisle

Question: How would you describe the research focus of your center?

Answer: Microorganisms provide us with great services that will improve the sustainability of human society by biodegrading contaminants, generating renewable resources and improving our health.

Microorganisms have an amazing diversity of metabolic capabilities. We can take advantage of these capabilities because chemicals that we consider pollutants usually are considered food for microorganisms. Many of the microorganisms will break down these contaminants to gain energy for their growth. In some cases, microorganisms transform the pollutants into something that is indispensable as feedstock to agricultural and industrial sectors of our economy. 

Through their metabolic ability, the right microorganisms can also improve our health. We work with Biodesign’s Center for Health Through Microbiomes to understand the microorganisms that inhabit us and help us stay healthy. 

Q: Why is this work important to society? 

A: Our work with microorganisms benefits society by removing environmental pollutants, creating renewable resources and enhancing human health. 

Environmental pollutants are harmful in a variety of ways — from things that could kill us outright to things that cause chronic issues, leading to cancer or problems with our neurological, cardiovascular or reproductive systems. 

Our society requires renewable resources. We need to create a circular economy for energy and materials. This is driven by the fact that we need to combat climate change and replace or at least minimize our demands on fossil fuels. They are finite. We waste them, and their dispersal into the environment creates risks to human and ecosystem health. 

Finally, we would love to have our human health be as good as possible so we can have a long and healthy life. 

Q: What do you think are the biggest challenges in this field of research?

A: Our field is extraordinarily interdisciplinary. Any researcher who will be successful in the field needs to know a lot about many topics. This requires a large investment of time to get up-to-speed.

The second biggest challenge is that we never have enough money. None of the projects we do are short term because they are complicated and interdisciplinary. We need long-term funding to develop the science base, apply that base to technological innovations and iterate between the two. 

Q: What is something you consider one of the center's greatest, biggest successes?

A: The center has achieved several things over the years, including spinning off two completely new Biodesign centers, developing membrane film technologies and producing alumni who go on to excel.

We have developed membrane-film technology that reduces water pollutants like nitrate and perchlorates. Since then, we've discovered so many other things that we can do with membrane-film technology. Perhaps the most exciting of them today is we can use membrane film technology to destroy the perfluorinated alkyl substances, also known as the forever chemicals because they do not break down in natural conditions, but bioaccumulate in the food chain and in humans. We use a combination of palladium catalyst film and a microbial biofilm to create a two-fill system that begins and completes the job of completely breaking down PFAS into harmless products. 

I'm also extraordinarily proud of our people. First, we have many students and postdocs who have worked in the center and then moved on to be exceptionally successful in academia or in industry. Many are now tenured professors at leading universities around the U.S. and the world. For example, one of my students is a member of the National Academy of Engineering, a truly big deal.

The first two professors I hired into the center, soon after I came to ASU, Rolf Halden and Rosa Krajmalnik-Brown, now head their own Biodesign centers. This is truly wonderful for them and feathers in the cap of the Biodesign Swette Center for Environmental Biotechnology.

Q: What are the ways that students are involved in your center's research?

A: I always tell my students, especially early on in their careers that I depend on them to produce most of the good ideas for the team. I excel at recognizing a promising idea when I see it and then working with them to develop it. 

When I work with PhD students, the research they do in the center forms the core of their dissertation. Most do experiments, some of them do mathematical modeling and all must take a lot of responsibility for their work. For example, the concept of creating a film palladium-based catalyst wasn't my idea but originated from one of my postdocs.

Bruce Rittmann working with a researcher in the lab
Bruce Rittmann working with a researcher in the lab. Photo by Andy DeLisle

Q: If someone gave your center $100 million, what would you do with it? 

A: Two things: field testing on more of our technologies and upgrading some of the physical facilities we have here at the center. 

In the first case, we need to be able to translate the results that we get in the laboratory to something bigger, more field-real. Therefore, I would invest a substantial fraction of the money in developing pilot-scale so we could do field testing. If we don't prove the technology in the field, nobody's going to buy the technology. 

Second, we must maintain tremendous experimental and analytical capabilities in the center. Thus, I would spend a piece of that money upgrading our capabilities. For example, some of the analytical instruments we have here are almost two decades old. I wouldn’t need to spend $100 million on equipment, but I would spend a piece of the funds to upgrade.

Q: What is the most fun aspect of your work in the center?

A: On the one hand, I truly love working with the students and the postdocs, particularly the ones who have lots of good ideas. 

On the other hand, I also love to write papers. We don’t know what we have in our research results until we have a manuscript formed. Writing is the intellectual discipline that allows us to sort the wheat from the chaff and be able to comprehend and express our most important results.

My appreciation for writing and using language well goes back to high school, where I had amazing English teachers. When working with students on papers, I often ask, “What was your most important research tool?” They might say, “Mathematical modeling, chromatography or DNA sequencing.” I reply, “No, it's English.” English is the most important research tool because it is how we organize our thinking and communicate it to others. 

Q: How did you become interested in science and in particular, the field you are in?

A: It all started with a telephone call. The father of what we now call environmental biotechnology, Professor Perry McCarty at Stanford University, called me and asked me to be his PhD student. I was working as a consulting environmental engineer in St. Louis, Missouri, but thought that I could do more by achieving a PhD. I was surprised by the call directly from Perry McCarty, but I composed myself enough to say that I would join him at Stanford. 

Working with Dr. McCarty opened my eyes to understanding how microorganisms work and made me eager to become a professor. I have been a professor first at the University of Illinois in Urbana-Champaign, then at Northwestern University and now at ASU. Each place was the right place at the right time for me.

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