Deborah Madden
MIT Department: Civil and Environmental Engineering
Faculty Mentor: Prof. Desiree Plata
Research Supervisor: Marc Foster
Undergraduate Institution: University of Georgia
Hometown: Kingston, Jamaica
Website: LinkedIn
Biography
Deborah Madden is a rising junior at the University of Georgia (UGA), where she is a Foundation Fellow and Stamps Scholar. She is majoring in Environmental Engineering, and her research interests lie in sustainability, water, energy, and circularity. Deborah works with Professor Jambeck in the Informatics Circularity Lab at UGA, where her research focuses on plastic waste and circularity analysis for cities across the US and the world. Deborah is currently interning in the Plata lab, researching the bacterial degradation of plastics in marine environments. Deborah intends to obtain a Ph.D. in Engineering focusing on energy and water infrastructure in small island developing states. She hopes to use the expertise she gains to better her home country of Jamaica. Outside of research, Deborah serves as the Pre-Collegiate Initiative Chair for the UGA chapter of the National Society of Black Engineers. This role has allowed her to actively mentor younger students in STEM and aligns with her passion for minority inclusion.
Abstract
Exploring the community interactions of marine bacteria to mineralize polyester plastics designed for degradation
Deborah Madden1, Marc Foster2 and Desiree Plata2
1Department of Environmental Engineering, University of Georgia
2Department of Civil and Environmental Engineering, Massachusetts
Institute of Technology
Biodegradable plastics are one part of the solution to plastic pollution as degradation is engineered in the chemistry of the plastic, unlike persistent commodity plastics. While their degradation in terrestrial environments is well-studied, marine biodegradation remains unclear. To explore this, bacterial species were isolated from PBAT/PBSeT plastic incubation in the Mediterranean Sea. Notably, Microbulbifer eichini degrades polyesters but does not consume the byproducts, suggesting that plastic degradation relies on bacterial community interactions rather than a single organism. Thus, we investigated the degradation ability of Microbulbifer e versus the whole community on PBAT/PLA blend film, an aromatic aliphatic co-polyester that biodegrades slowly in soils. Colony forming unit counting was used to show whether the bacteria lived off polymer-derived carbon. The percent mineralization of plastic was measured by determining CO2 produced using cavity ring down spectroscopy, and analysis of the accumulation of monomer products was quantified by liquid chromatography coupled to mass spectrometry. With concrete evidence showing that Microbulbifer e breaks down but does not mineralize PBAT/PLA blend film, we shed light on the nuanced dynamics of microbial communities’ ability to degrade aromatic aliphatic co-polyesters. This research will better inform the design of new polymers that break down under natural conditions.
