Avaliação da capacidade de microrganismos isolados de sedimento marinho da Bacia de Pelotas na formação de biofilme em polietileno de alta densidade

Abstract

Plastic can be classified as thermosets or thermoplastics resins. In 2017, the world production of thermoplastic resins was approximately 348 million tons, with processed plastics production reaching around 355 million tons. When reach the oceans, they can be broken down into microplastics and nanoplastics. In this ecosystem, there are microorganisms with the capacity of adhesion and degradation of several plastics. Polyethylene present high durability and resistance, in addition to a very low rate of biodegradability, making it widely used by transformation industry. This work aimed to evaluate the capacity of bacterial and yeast strains isolated from deep-sea sediment of the Pelotas Basin (Brazil) in adhesion and biofilm formation on high density polyethylene (HDPE). Bacteria were identified as Pseudomonas, Stenotrophomonas or Lysinibacillus and yeasts as Candida parapsilosis. Three bacterial and two yeast isolates showed ability to adhere or form not induced biofilms in 24 and 48 hours of incubation. The data obtained through analysis of Crystal Violet Assay, Scanning Electron Microscopy and Atomic Force and Fourier Transform Infrared Spectroscopy, indicated that the bacterial isolates formed mature biofilms, whereas yeast isolates showed only an initial pattern of adhesion to non-aged and aged HPDE. In addition, each isolate showed a different pattern regarding its capacity for adhesion or biofilm formation, which varied in relation to the time of biofilm production, as well as the aging of HDPE. These data provide unprecedented knowledge about microbial species of deep marine sediment from a Brazilian ecosystem, which can be indicative of their ability to aggregate in plastic fragments in their native environment, as well as of biodegradation of these polymers.