Faculty Sponsor: Dave Wessner
Microplastic pollution is a rapidly growing form of aquatic contaminant. In addition to concentrating persistent organic pollutants on their surfaces and imbedding in the digestive tracts of organisms that ingest them, microplastics also may serve as vectors for the movement of pathogens. The hydrophobic surfaces provide a substrate for bacteria to attach to, forming biofilms that are distinct from the free-living bacterial communities and biofilms of non-plastic substrates. This study aims to investigate the attachment of bacteria to different types of plastic. Microplastics were collected in surface trawls from estuaries along the southeastern coast of the U.S. Chemical composition of environmental microplastic pollution was identified through FTIR analysis, which was followed by culture-based analysis assessing the presence of active biofilms on the plastics. Polyethylene was found to be the most abundant form of microplastic pollution, accounting for over half of the samples. The proportion of plastics with active biofilms did not differ between chemical compositions, but all plastic substrates fostered a higher proportion of biofilm development than non-plastic substrates. In vitro analysis of microplastic-isolated bacterial attachment was measured on high-density polyethylene, low-density polyethylene, polypropylene, and polyvinyl using a modified crystal violet biofilm assay. Previous literature has suggested that bacteria prefer to attach to hydrophobic substrates. In attachment analyses, bacteria attached to polystyrene most abundantly even though it was the least hydrophobic substrate, suggesting that bacterial attachment is influenced more heavily by another surface property.