Biodegradação de hidrocarbonetos de petróleo pela atuação de fungos endofíticos isolados da Eichhornia crassipes (Mart.) solms de ambiente aquático da Amazônia

Abstract

The interest in the study of environmental contamination by polycyclic aromatic hydrocarbons (PAH) lies in the fact that most of these compounds are potentially carcinogenic and mutagenic. Microorganisms play an important role, since they use these substances as a source of energy. In this study, the fungal isolates of the macrophyte Eichhornia crassipes (Mart) Solms were selected in medium BH (Bushnell Haas) containing the crude technique based on redox indicator 2, 6 - dichlorophenol indophenol (DCPIP), by means of oxidation occurring biological indicated by a change in coloring of the culture medium. Standing out this test, the fungi encoded F13, F14 and F01, respectively, Phoma herbarum, Fusarium moniliforme and Penicillium citrinum, which exhibited biological activity between 24 and 48 hours. In order to contribute to the advancement in research on bioremediation this work developed studies on hydrocarbon degradation using fungal consortium in liquid mineral medium (BH) supplemented with 15 uL of crude oil using bioaugmentation and biostimulation tests in different biodegradation times: time 0, 48 hours, 96 hours and 7 days. To evaluate the oil degradation behavior by fungi were performed by quantitative analysis of polycyclic aromatic hydrocarbons (PAH) from the application of analytical methods: liquid-liquid extraction of the sample supernatant in the presence of oil (in accordance with EPA Method 3510C) and under the action of fungal consortium. Then there was the cleaning step and fractionation of the sample in open column (EPA Method 8270D modified) obtaining a fraction of the HPA for the analysis of 16 compounds, considered of medium polarity and established as priorities by the Environmental Protection Agency States (US EPA); and as a last step: separation and quantification of hydrocarbons by gas chromatography-mass spectrometry (GC-MS). The analytical curves showed determination coefficient values (R2) above 0.99 for the 16 HPA. The mean recovery values for p-terphenyl surrogate added to the samples before the extraction stage were in the range of 67.15/99.06%. The investigation of the possible degradation of these recalcitrant compounds demonstrate the potential of these fungi in a consortium, which was observed during the 7 days of the experiment and the decrease in individual concentration of the analyzed compounds. These results allow to observe the crude oil degradation behavior and infer that the samples with pH correction acid without additional source of nutrients showed to be more efficient in the degradation of HPA 16 within 7 days with the reduced concentration of between 179.56 ± 0.07 to 77,00 ± 0.21 ng mL-1 equivalent to 64% degradation. The normality test of Shapiro-Wilk proved that the data does not follow a normal distribution, with p-value 0.02 (<0.05). The ANOVA analysis showed that time directly influences the degradation. It is believed that this study contributes to the numerous studies on bioremediation in the Amazon in order to advance the research on the reduction of environmental contaminants, particularly aromatic hydrocarbons.