Research Areas

1,4-Dioxane is a probable carcinogen that impacts human and environmental health. The compound has been used historically as a solvent stabilizer, and modern use is mainly as a solvent for plastic, personal care, and cleaning products. Due to its high mobility and persistence, 1,4-dioxane has been shown to contaminate groundwater and drinking water supplies.

Our research focuses on developing tools to understand and engineer bioremediation solutions of 1,4-dioxane. Pseudonocardia dioxanivorans CB1190, a bacterium that uses 1,4-dioxane as a metabolic energy source, was characterized by Dr. Shaily Mahendra to study the biochemical and environmental conditions that influence 1,4-dioxane and co-contaminant biodegradation. Using molecular biology, analytical chemistry, and microbiological techniques, we are able to quantify contaminant transformation, identify biodegradation pathways, and link microbial activity to 1,4-dioxane remediation.

This work advances bioremediation as a sustainable alternative to energy and chemical intensive treatment technologies by enabling in situ and engineered biological solutions for 1,4-dioxane in groundwater, wastewater, and industrial waste streams.

Selected Publications:

Polasko, A. L.; Zulli, A.; Gedalanga, P. B.; Pornwongthong, P.; Mahendra, S. A Mixed Microbial Community for the Biodegradation of Chlorinated Ethenes and 1,4-Dioxane. Environ. Sci. Technol. Lett. 2019, 6 (1), 49–54. https://doi.org/10.1021/acs.estlett.8b00591. (ACS Editor’s Choice)

Zhang, S.; Gedalanga, P. B.; Mahendra, S. Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures. Environ. Sci. Technol. 2016, 50 (17), 9599–9607. https://doi.org/10.1021/acs.est.6b02797.

Per- and polyfluoroalkyl substances (PFAS) comprise a family of over 16,000 synthetic compounds widely used in industrial and consumer products for their thermal stability and inertness, yet their exposure has been linked to adverse human health outcomes and interference with microbial community function.

Given the energy- and cost-intensive nature of most existing PFAS destruction technologies, we aim to develop sustainable and efficient PFAS removal strategies using fungi, whose unique oxidative enzymes enable the transformation of complex and persistent contaminants. We isolated more than 100 fungal strains from AFFF-contaminated soil and groundwater. Several strains of environmental fungi, such as Phanerochaete chrysosporium, were verified to biotransform fluorotelomer alcohols (FTOHs). We are also working on characterizing the mechanisms underlying fungal PFAS tolerance and potential transformation using whole genome sequencing and multi-omics tools (proteomics and metabolomics).

Our work will contribute to a broader understanding of fungal detoxification pathways, and provide insights into the in situ bioremediation of PFAS.

Selected Publications:

Shah, K.; Ray, S.; Bose, H.; Pandey, V.; Wohlschlegel, J. A.; Mahendra, S. Proteomics Insights into the Fungal-Mediated Bioremediation of Environmental Contaminants. Current Opinion in Biotechnology 2024, 90, 103213. https://doi.org/10.1016/j.copbio.2024.103213.

Merino, N.; Wang, N.; Gao, Y.; Wang, M.; Mahendra, S. Roles of Various Enzymes in the Biotransformation of 6:2 Fluorotelomer Alcohol (6:2 FTOH) by a White-Rot Fungus. Journal of Hazardous Materials 2023, 450, 131007. https://doi.org/10.1016/j.jhazmat.2023.131007.

Tseng, N.; Wang, N.; Szostek, B.; Mahendra, S. Biotransformation of 6:2 Fluorotelomer Alcohol (6:2 FTOH) by a Wood-Rotting Fungus. Environ. Sci. Technol. 2014, 48 (7), 4012–4020. https://doi.org/10.1021/es4057483.

Plastic production has exponentially increased globally as single-use polymers have become essential across consumer, industrial, and medical sectors. 400 million tons of plastic are produced annually which has overwhelmed our ability to safely handle and dispose of this non-biodegradable waste. 

Our research is focused on testing the biodegradability properties of polymers with a particular focus on single-use catheters. Using integrated biochemical and analytical approaches, we evaluate enzymatic and microbially mediated polymer degradation and quantify polymer biodegradation. In parallel, we study biofouling-resistant polymer materials by investigating how microbes interact with polymer surfaces, using molecular and biological methods to quantify biofilm formation, microbial biomass, metabolic activity, and extracellular matrix production.

This work supports the design of polymer materials for medical and environmental applications that balance performance and biodegradability. The aim is to develop safe medical devices while reducing the long-term environmental and health burdens of single-use plastics.

Selected Publications: 

Polasko, A. L.; Ramos, P.; Kaner, R. B.; Mahendra, S. A Multipronged Approach for Systematic in Vitro Quantification of Catheter-Associated Biofilms. Journal of Hazardous Materials Letters 2021, 2, 100032. https://doi.org/10.1016/j.hazl.2021.100032.

McVerry, B.; Polasko, A.; Rao, E.; Haghniaz, R.; Chen, D.; He, N.; Ramos, P.; Hayashi, J.; Curson, P.; Wu, C.-Y.; Bandaru, P.; Anderson, M.; Bui, B.; Sayegh, A.; Mahendra, S.; Carlo, D. D.; Kreydin, E.; Khademhosseini, A.; Sheikhi, A.; Kaner, R. B. A Readily Scalable, Clinically Demonstrated, Antibiofouling Zwitterionic Surface Treatment for Implantable Medical Devices (Adv. Mater. 20/2022). Advanced Materials 2022, 34 (20), 2270152. https://doi.org/10.1002/adma.202270152.

Tire and road wear particles (TWPs) are released into the environment globally exceeding one million tons per year. Along with TWPs, large quantities of tire additives, as well as derivatives formed during tire production and transformation products generated during tire use, are also introduced. Tire derived chemicals (TDCs), such as 6PPD-quinone, have raised increasing concern due to their wide detection in surface water and stormwater, and the growing evidence on their toxicity.

With the urgent need of developing novel or enhanced treatment strategies for TDCs, our lab will focuses on expanded exploration on the capacity of bacteria and fungi to degrade these emerging contaminants. Building on our extensive bacterial and fungal collection resources, we plan to conduct systematic screening on their potential to degrade a broader range of TDCs. We are also going to employ molecular biological approaches, such as qPCR, to characterize microbial responses and to identify functional genes and proteins involved in TDCs transformation. In addition, TDCs transformation pathways and the toxicity of their transformation products will be further elucidated.

Our work aims to provide a more comprehensive understanding of the fate of TDCs under microbial activity, and offer valuable insights for their future detoxification and remediation.