The Effects of Pristine and Aged Microplastics on Biofilm Formation and Antibiotic Production

Polypropylene microplastics are some of the most abundant plastic pollutants in the environment. These microplastics provide ideal surface area for the formation of biofilms that can increase the spread of harmful contaminants, such as heavy metals, pathogens, and antibiotics. The current study examines the differences in how pristine microplastics and UV-light aged microplastics affect microbe biofilm formation and production of antibiotics in a 96-well microplate. While many laboratory studies utilize pristine microplastics to determine their effects, pristine microplastics are not always representative of the natural environment. The quick UV aging process allows us to examine how biofilms may form on microplastics that have existed in the environment and degraded naturally for longer periods. Various combinations of a locally sampled soil microbe suspension in water and Streptomyces pure culture were filled in a control condition 96-well microplate and absorbance readings were taken on a weekly basis. Experiments in process include six microplates with added plastics to compare biofilm growth. Each week after reading, successive plates will be scraped out and dilution plated to compare absorbance readings with counted colonies to validate the microplate method over a three-week growth period. Meanwhile, the scraped biofilms will be utilized in several zone of inhibition tests to qualitatively assess antibiotic production.