Brozel Lab
We are a bacterial ecophysiology lab, and we're all about looking into the fascinating world of life underground.
Research Interest
To build and maintain populations in soil, bacteria must contend with nutrient limitation in a competitive environment. This is different to clonal populations growing in nutrient-rich laboratory media.
In soil, rapid growth to high density can only occur in nutrient hot spots such as organic substrates exuded by growing roots. Yet, hot spots attract diverse taxa, leading to competition among species.
Rapid-growing model species such as Escherichia coli, Bacillus subtilis and Pseudomonas fluorescens shaped our bacterial physiology mindset that bacteria grow exponentially to stationary phase, survive for a while and eventually die. The phenomenon rests on the provision of organic compounds, such as sugars and amino or organic acids, replenished regularly.
Outside of nutrient hot spots, soil does not receive regular input of organic carbon. For species to maintain populations in nutrient-limited soil, they must focus on maintenance rather than growth. Thus, soil bacteria likely evolved to preserve resources for long-term population maintenance.
Successful population maintenance under nutrient-limiting, competitive conditions should include the development of both cooperative and competitive mechanisms. Networks of cooperating bacteria may contribute specific functions such as hydrolyzing complex carbohydrates or fixing atmospheric nitrogen. Conversely, taxa in competition would exert deleterious factors without expending excessive energy.
To address these questions, we study soil bacteria under soil-mimicking conditions.
I started out in food science but soon found bacteria more interesting. After completing a B.S. in food science in the beautiful Stellenbosch, South Africa, I pursued M.S. and Ph.D. at the University of Pretoria. I liked being a student so much that I never left university, teaching and mentoring students while studying how bacteria behave outside the Petri dish – ecophysiology. My work at the University of the Western Cape (1994-97) and later back at the University of Pretoria (1998-2003) focused on bacterial biofilms in industrial and drinking water systems.
I moved to South Dakota State University in 2003. Living in the agricultural heartland of the U.S. redirected my focus underground to the bacteria in soil. The prairie is home to rich microbiota, with many to-be-discovered phenomena lost during crop monoculture.
I am a third-year Ph.D. student. I work with the soil bacterium Bradyrhizobium, trying to unfurl the various phenotypic heterogenous populations within the so-called homogenous pure culture. I am also working to isolate novel Bradyrhizobium strains from various soil types from the U.S. and South Africa. In our recently published research, we characterized Bradyrhizobium populations from the established soybean fields using the culture independent methods. It is the first ever species-level characterization so far for Bradyrhizobium. My hobbies are gardening, cooking and trying new dine-in places.
I come from Pakistan, and I did my M.S. in microbiology at the Government College University Faisalabad.
I have an interest in exploring the bacterial world, especially in soil.
I am currently working on:
- Response of Bacillus cereus when encountered by growing roots.
- Why Bacillus populations in soil do not increase in numbers despite being fast-growing bacteria.
I am pursuing Master’s in plant science under Srinivas Janaswamy, co-supervised by Volker Brozel and Sen Subramanian. I liked to see colorful microorganisms growing, and I was curious about how these tiny organisms played major roles in human health, plant health and the environment, which inspired me to start my research career in microbiology. Currently I'm working on the encapsulation of nitrogen fixing bacteria using alginate for cereal crops to increase the yield.
I am from Nepal and have completed my M.S. in soil science. I am currently doing my Ph.D. in agricultural and biosystems engineering with my adviser Lin Wei. I am carrying out my research on biochar-based fertilizers and their interaction with soil microbes in maize cultivation. I am gaining valuable knowledge and skills on different free-living, nitrogen-fixing microbes in Volker Brozel’s lab. This is the preliminary work for my Ph.D. research in which I will be analyzing if various nitrogen-fixing microbes can associate and grow on biochar.
I am from Nepal, where I completed my master's in medical microbiology. Currently, I am pursuing a Ph.D. program in microbiology, focusing on the fascinating world of nitrogen-fixing bacteria. My passion lies in uncovering the cellular and molecular intricacies of microbiology — areas that were difficult to explore due to resource limitations in my home country. Joining SDSU provides a unique and transformative platform to deepen my understanding of these complex microbial processes, helping me fulfill my long-standing academic and professional aspirations. Besides my research, I enjoy cooking and planting.
Fall 2025
I am pursuing a B.S. in microbiology at South Dakota State University. My research in Volker Brozel’s lab, under the mentorship of Ph.D. student Muhammad Yasir Afzal, focuses on bacterial sporulation and germination. I discovered my passion for microbiology after taking Brozel’s microbial physiology course, which inspired me to join the lab and begin hands-on research. Outside of the lab, I serve as president of the Interfraternity Council and have held leadership positions in the Pi Kappa Alpha fraternity and the Order of Omega. I also enjoy doing anything outdoors, including hunting, fishing, camping, hiking and rock climbing.
Fall 2024, ongoing
Topic of Research: Characterizing a putative diazotrophic Streptomyces culture isolated from natural grassland.
I am a senior biochemistry student with a passion for microbes, soil and the environment. My research focuses on utilizing culturing, microscopy and molecular techniques to unveil how a Streptomyces isolate is able to grow without combined nitrogen. I completed a Research and Extension Experiences for Undergraduates program with Volker Brozel in fall 2024 and spring 2025, and I am currently supported by a Hoch Family Undergraduate Research Fellowship.
Spring 2024, ongoing
Topic of Research: Bacterial antagonists of Bacillus in soil.
Recent Graduate Students
- Armaan Kaur Sandhu, Ph.D. (2024)
- Bikram Das, Ph.D. (2022)
- Amrit Koirala, Ph.D. (2021)
- Amina Baniya, M.S. (2020)
- Gitanjali NandaKafle, Ph.D. (2018)
- Bibha Dahal, M.S. (2016)
Previous Graduate Students
- Nabilah Alshibli, M.S. (2018)
- Laura J. White, Ph.D. (2017)
- Tyrel Deutscher, M.S. (2016)
- Ryan Schmid, M.S. (2014)
- Elizabeth A. Rettedal, Ph.D. (2011)
- Ursula Waack, M.S. (2011)
- Kelly Lehnert, M.S. (2008)
- Amy Christie, M.S. (2006)
- Yun Luo, M.S. (2006)
Recent Undergraduate Students
- Jieun Kim, summer 2024
- Kallie Crowl, fall 2022-summer 2023
- Cole Adam, fall 2021-spring 2022
- McKenzie Brown, spring-fall 2022
- Mitchal Eichacker, spring 2023
- Emma Osmundson, fall 2022
- Amelia (Mia) Thoennes, fall 2021-summer 2022
- Laney Brown, spring 2021-2021