WAESO Conference Abstract

It was recently discovered that drinking water all around the world contains microplastics that have made their way from wastewater into the environment and back to drinking water treatment plants. Microplastics are any piece of plastic smaller than 5 mm. They are small enough that they do not get filtered out during the water treatment process so they end up in our water supply and can continue back on a cycle of contamination. Microplastics are found in 94% of the tap water in the United States. The human and ecosystem health implications of this are not fully known however this is an emerging issue that will most likely require innovation and the design of strategies to reduce the amount of  microplastics contamination in our recreational and drinking water supply. One proposed solution is the use of microbes to aid in the biodegradation of microplastics. Several studies have shown that Pseudomonas putida and Pseudomonas fluorescens have been found to grow on polyvinyl chloride (PVC), while Pseudomonas stutzeri has been found to grow on hydroxybutyrate. Studies have shown that, in addition to colonizing microplastics, Pseudomonas species may play a role in the decomposition of plastics such as polyvinyl alcohol (PVA), polypropylene and polythene. This raised the question of, what types of microplastics can different Pseudomonas species colonize and biodegrade? The purpose of this project was to determine if Pseudomonas stutzeri along with other Pseudomonas species (Pseudomonas aeruginosa, Pseudomonas putida, and Pseudomonas fluorescens) are capable of colonizing plastic types PVC (plastic type 3), Low-density Polyethylene (LPDE) (plastic type 4), Polypropylene (PP) (plastic type 5), and Polystyrene (plastic type 6). The initial goal of this project was to establish protocols for the colonization, isolation, and genetic identification of the Pseudomonas species from each of the four microplastics tested.

To achieve this goal,  Pseudomonas stutzeri was grown on Pseudomonas Isolation Agar (PIA) and Pseudomonas fluorescens (PF) agar to determine the characteristic colony morphology. ribosomal-16S primers were also used to identify the genetic relationships between P. stutzeri, P. aeruginosa, P. putida, and P. fluorescens. SEM was used to image the microplastics that were co-incubated with the different Pseudomonas species at 20x, 620x, 1150x, 4400x, and 7500x. Future studies will be used to determine which Pseudomonas species can aid in the biodegradation of microplastics PVC 3, LPDE 4, PP 5, and PS 6 .