Polystyrene biodegradation by microorganisms isolated from Sphenophorus levis microbiota

Abstract

Polystyrene is a polymer that, as other plastics, presents versatile physical and chemical properties, enabling the production of a wide variety of items for distinct applications with low cost. Proportional to the increasing demand for this material, its accumulation is evident, causing social and ecosystem problems. In parallel, many researches have been conducted aiming this plastic biodegradation by observing natural events. In this context, it was verified thar larvae from some insects are able to use polystyrene as a carbon source, what would be related to their gut microbiota. Therefore, this project has the aim of using Sphenophorus levis larvae, which was observed in our laboratory ingesting expanded polystyrene, as a research model for the search of microorganisms and key gene in the biodegradation process of this material. The insect larvae will be submitted to a diet restricted to this material and the gut microbial diversity will be compared to the profile from artificial diet fed animals. Cultivable microorganisms will be collected from the insect's gut for the enrichment process in a culture media in which the polystyrene is the only carbon source. The microorganisms will be isolated and cultivated above a polystyrene film. The biofilm formation and the material modifications will be analysed. With the sequencing of the bacteria genomes, genes associated to the degradation processes will be identified and their expression levels will be evaluated by RT-qPCR. The ORFS from superexpressed genes will be cloned and heterologously expressed for enzymatic characterization, by colorimetric assay.