Dr. Erica Marie Hartmann began her research career at the Johns Hopkins Bloomberg School of Public Health, where she worked as on mass spectrometry-based methods for detecting microbial enzymes necessary for bioremediation. From Hopkins, she moved to Arizona State University where she was the first graduate of the interdisciplinary Biological Design PhD program. Following her graduation, she was awarded a Fulbright to study microbes that degrade the toxic, carcinogenic pollutants known as dioxins in France at the Commission for Atomic Energy. She began leading studies on the effects of antimicrobial chemicals on the microbes found in indoor dust at the Biology and the Built Environment Center at the University of Oregon and is currently continuing that work as an assistant professor at Northwestern. You can contact her via Twitter or Instagram.


Ryan Blaustein completed his Ph.D. in the field of Microbial Ecology at the University of Florida (2017) and recently began his Post-doc in the Hartmann Lab. His dissertation incorporated bacterial genomics and bioinformatics to define the transitions in the structure and function of the citrus microbiome that are associated with citrus greening disease progression and antimicrobial treatment. Ryan previously earned his B.S. in Biology (2011) and M.S. in Environmental Microbiology (2014) from the University of Maryland. See more about Ryan on his personal site.

Ratanachat "Siam" RacharaksRatanachat “Siam” Racharaks completed his Ph.D. in Chemical and Environmental Engineering at Yale University (2020) and is currently a Post-doc in the Hartmann Lab. His dissertation focused on the development of microbiological techniques and CRISPR genetic engineering tools for a recently rediscovered cyanobacterial strain and utilized these tools to demonstrate the potential of this novel strain to produce commodity chemicals. Siam previously earned his B.S. (2012) and M.S. (2014) in Food, Agricultural, and Biological Engineering from the Ohio State University. His current research interests include designing and optimizing synthetic biology tools, such as phagemids, that are effective with diverse microbes for applications in biotechnology and health science.

Graduate Students

Jinglin Hu is a Ph.D. student in the Department of Civil and Environmental Engineering at Northwestern University. She received her B.S. in 2016 from the University of Minnesota in Bioproduct and Biosystem Engineering. Her current research interests include abiotic and biotic transformations of indoor air pollutants and the characterization of indoor microbiome.

Alex McFarland went to the College of William and Mary to study biology and performed undergraduate research in a biochemistry lab. After graduating, he moved to the Caribbean to become a divemaster and became interested in the connection between coral health and microbial communities. He joined the Hartmann lab in May 2017 and is interested in using and developing molecular and bioinformatic tools to better understand how humans impact and are impacted by microbial communities in the built environment. He is a Ph.D. student in the Interdisciplinary Biological Sciences Program.

Jiaxian Shen is a PhD student in the Department of Civil and Environmental Engineering at Northwestern University. She received her Bachelor’s degree in Environmental Engineering from Zhejiang University, China. As an undergraduate, she performed research on microbes that drive the global carbon and nitrogen cycles. She also studied the biodegradation of polychlorinated biphenyls (PCBs) in soil and slurry. Jiaxian decided to join the Hartmann lab because she is very interested in improving human health and maintaining a sustainable environment from a microbial perspective. One unique fact about Jiaxian is that she is a big foodie; she loves to discover new and exciting cuisines from around the world.

Olivia Barber has a Bachelor’s degree in Civil and Environmental Engineering from University of Maryland, College Park and a Master’s degree in Environmental Engineering from Imperial College London. Her dissertation focused on barriers to the implementation of novel microbial wastewater treatment in Serbia. After completing her Master’s, Olivia spent a year working in industry as a consultant engineer before returning to academia. Olivia is interested in improving the quality of the indoor environment to create a positive health impact on occupants.

Hanna Bertucci is currently a senior at Northwestern studying biology on the pre-medical track. She has been investigating the mechanisms of antibiotic resistance in the Hartmann lab since her sophomore year.

Nancy Hellgeth is a Northeastern Illinois University student majoring in Biology. She is interested in the role of environmental and human microbiota in the etiology of chronic disease, and the impact that common chemicals have in shaping these microbial communities. She is also interested in the overlap between the gut microbiome and host immune system.

Mia Tran is currently a junior at Northwestern studying environmental engineering. Originally from Chicago, she has a strong interest in the intersection of arts and sciences, and is excited to dip her toe into the realm of research with Hartmann lab. Mia also pursues graphic design and hip-hop/urban dance on the side.

Tyler Shimada is currently a junior at Northwestern studying chemical engineering on the pre-med track. He is from Chicago and his hobbies include swimming, fishing, Rubik’s Cubes, and origami.

Sherlyn Weng is a junior at Northwestern studying environmental engineering and integrated science program. This is her first time doing microbiology research and she’s excited to explore the environmental profile of antibiotic resistance in a hospital setting. Outside of the lab, Sherlyn is involved in City Health Tech, which is a student startup with a mission to improve campus infection control.