Date of Award
8-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Environmental Engineering and Earth Science
Committee Chair/Advisor
Dr. Kevin Finneran
Committee Member
Dr. David Freedman
Committee Member
Dr. David Ladner
Committee Member
Dr. Francisco Barajas
Abstract
Microplastics (MP) are ubiquitous in the natural environment and are a growing threat due to their small size and durability. Plastics are released into the environment through improper waste management, wastewater treatment outfalls, industrial spills, agricultural runoff, and landfills. These particles breakdown into secondary MP through degradation pathways. MP, less than 5 mm, require intricate removal techniques from water systems. Filtration techniques, though viable and effective, have implementation constraints due to high cost, maintenance demands, and filter fouling. By integrating coagulation and flocculation processes prior to filtration, MP removal efficiencies can increase, while minimizing operational challenges during filtration. Extracellular polymeric substances (EPS) are produced from bacteria and are stimulated under stressful environmental conditions. By leveraging Pseudoalteromonas sp. NCIMB 2021’s biofilm-forming capacity, MP can become embedded in the EPS matrix. When Pseudoalteromonas sp. NCIMB 2021 was grown in limited nutrients, at pH 6.28, at salinity 35 ppt, and at 37°C, a maximum removal capacity of 74% was reached for high density polyethylene (HDPE.2). Piecewise environmental conditioning determined temperature, 37°C, to be the most significant factor in aggregate formation when tested with MDPE. Various plastic polymers were examined for their removal efficiencies determining, HDPE.2 (74%), high-density polyethylene creamer bottle (HDPE.B) (56%), polyethylene terephthalate (PET) (52%), polypropylene (PP) (51%), polyamide (PA) (51%), and polyvinyl chloride (PVC) (43%) removal efficiencies when grown in ideal conditions. When grown in suboptimal conditions, removal efficiencies were significantly altered. This suggests that plastic sorption capacities are influenced in environmental conditions altering aggregate formation, and therefore removal of MP.
Recommended Citation
Mercer, Janelle L., "The Aggregation of Microplastics by Enhancing Extracellular Polymeric Substance Production in Pseudoalteromonas sp. NCIMB 2021 to Improve Removal Efficiencies in Environmental Matrices" (2026). All Theses. 4837.
https://open.clemson.edu/all_theses/4837
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