Microbial Processes of Environmental Plastic Weathering and Biodegradation in Natural Systems

M.B. Duhaime, R.N. Cable, J.K. Choi, A. Mizrahi, L. Michaelson, A. Bhaumik, C. Plotzke, S. Zhang, T. Lin, P. Thakre, Y. Tan, J. Hu, D. Meunier, Y. Lai, Z. Chen
University of Michigan,
United States

Keywords: bacteria, fungi, polyethylene, biodegradation, biofilm, freshwater


Plastic waste is increasingly ubiquitous in the environment, representing both an important material resource loss and potential environmental and health risk. This global concern requires a data-driven understanding of the fate and effects of plastics in the environment. Microbes, which are also environmentally ubiquitous and abundant, may play a key role in determining the fate of plastics. Recent work has shown that microbial biofilms in aquatic systems can alter plastic particle densities, and through metabolic mechanisms microbes can contribute to plastic polymer degradation. In order to assess how microbial processes affect the fate of polyolefins in freshwater systems, we pair microbiological and chemical analysis of polyethylene samples colonized both in situ and in laboratory settings. Our approach allows us to compare the biofilm formation and biodegradation potential of microbial consortia found in the environment with single-strain cultures of known polyolefin degraders. We have found that microbial colonization of plastics in the environment is specific to polymer formulation and UV weathering. We have determined the rates of biofilm growth in the environment, as well as plastic-derived carbon remineralization by biofilms in the laboratory. Such discoveries are essential to the understanding and modeling of plastic fate in aquatic environments. This work is a necessary step in both reducing the accumulation of plastic waste and designing new circular strategies for the reuse of plastic waste.