Produção de inóculo microbiano, obtido de macrófitas aquáticas na Amazônia, com potencial de degradação de hidrocarbonetos de petróleo

Abstract

The Amazon, which owns the largest fauna and flora in the world presents unparalleled wealth of biological diversity, however, keep intact this megadiversity requires scientific and technological knowledge. In this context, there is an important biotechnological tool that is the bioremediation of impacted environments with petroleum hydrocarbons and derivatives. In the present study samples of microbial communities of fungi and bacteria associated with aquatic macrophytes Eichhornia crassipes (Mart.) Solms, Ichnanthus calvescens Döll and Cyperus ligularis L., were researched. These host plants common at Rio Negro were collected in contaminated environments by oil and oil products at Waterway Station from Manaus. From the species selected, 155 bacterial strains were isolated, being 97 epiphytic and 58 endophytic, and 54 fungi strains, being 30 epiphytic and 24 endophytic. Selective media were used for isolation of microorganisms such as BH liquid medium (Bushhnell Haas) plus oil. The oil and diesel used are from the Base Oil Urucu, Amazonas. The biodegradability tests were performed on selective medium (BH), with the addition of oil as the carbon source known as Medium I This test was repeated with the addition to the medium I the redox indicator 2,6-dichlorophenol indophenol (DCPIP), called medium II. After the evaluationof microbial isolates were selected 6 bacteria and 7 fungi. Molecular identification of bacteria was performed by the 16S ribosomal DNA region and revealed the presence of Bacillus pumilus (endophytic / epiphytic), Lysinibacillus fusiform (epiphytic), Pseudomonas aeruginosa (epiphytic) and Acinetobacter junii (epiphytic/epiphytic). For molecular identification of fungi was performed by the ITS1 and ITS2 region and revealed the presence of Curvularia trifolii (epiphytic), Curvularia clavata (endophytic / epiphytic), Gibberella intermedia (epiphytic/endophytic), Phoma herbarum (epiphytic) and Dothideomycetes sp (epiphytic). These microorganisms were selected for composition of microbial consortium that were used for hydrocarbon biodegradation tests. The measurement of biodegradation of oil and diesel activities was estimated by chromatography and mass spectrometry. In tests we used water of Rio Negro with the aim of approaching research the environment that are being studied. Degradation of hydrocarbons by consortia of fungi and bacteria had significant average values (98.7 to 100%), but did not show any statistical difference between the degradation of the control containing water of the Rio Negro (97.3%). In the experiment with the mixed consortium (FB), there were significant differences, because although the control containing water of the Rio Negro has promoted degradation of diesel by wild microbiota (81.7%), this degradation was lower and statistically different from the mixed consortium (97,5%). Analysis were carried out for degradation of the compounds naphthalene and phenanthrene of diesel by consortia . It was observed that phenanthrene was the best that has been degraded by the mixed consortium (F / B), however the naphthalene was better degraded by the control containing only water from the Rio Negro, highlighting the potential of wild microorganisms that deserve attention in future research, the isolation of these ones in waters from Rio Negro. In the experimental design with the consortia, the results showed that mixed consortia (FB) have potential for use in future bioremediation.