Biodegradação do fungicida piraclostrobina em água utilizando as bactérias bacillus subtilis e pseudomonas aeruginosa.

Abstract

Fungicides are applied in various agricultural practices to reduce microbial load and enable high productivity. Prolonged exposure to these pesticides harms the environment and affects the health of humans and other forms of life, which is why the degradation of these compounds through microbial bioremediation has been the focus of numerous studies. With the objective of studying the bacterial biodegradation of the fungicide pyraclostrobin in liquid media, this dissertation brings together a review article with bibliometric analysis and an article with experimental data. The bibliometric analysis was carried out using the terms “biodegradation” and “fungicides”, focusing on bioremediation using bacteria and microbial consortia for the last 10 years. Twenty articles were selected from the Scopus database based on keywords and the Biblioshiny software was used to carry out a detailed analysis of the publications. There was an increase in publications related to microbial bioremediation, with studies on strobilurins showing increasing scientific interest. Among the countries that made the most contributions in the area, Greece stood out. In the dissertation's experimental research, the biodegradation of the fungicide pyraclostrobin (a strobilurin) in water was evaluated. The experiments were carried out using a complete factorial design in which two variables were used, the bacteria (Pseudomonas aeruginosa and Bacillus subtilis) in isolation and the time of exposure to the fungicide (5 and 10 days). The experiments with bacteria in a consortium were conducted for 5 days. The samples were analyzed by High Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD) and Liquid Chromatography coupled to Mass Spectrometry (LC-MS). The results showed that both bacteria biodegraded pyraclostrobin, with Pseudomonas aeruginosa showing a significantly higher degradation rate (57.9% in ten days). The consortium between bacteria did not show better results when compared to Pseudomonas aeruginosa used alone; therefore, it did not present synergistic effects capable of leading to an increase in the biodegradation of pyraclostrobin. It was concluded that the biodegradation of pyraclostrobin by Pseudomonas aeruginosa demonstrated promise for the removal of this fungicide when dispersed in a liquid medium. However, more research is still needed to focus on the use of consortia between different microorganisms to improve degradation rates and the efficiency of removing these compounds from the environment.