Bioremediation of contaminated soils with diesel oil: structural and functional analysis of the microbial community

Abstract

The diesel oil is the main fuel in the Brazilian energetic matrix, being the petroleum derivative most commercialized in Brazil. This fuel is a complex mix of hydrocarbons and, due to its recalcitrance and frequent spill accidents, it is worldwide recognized as a threat to aquatic and terrestrial ecosystems. Several techniques are available to the remediation of sites contaminated with hydrocarbons. However, the bioremediation is considered a promising alternative since it is more sustainable, efficient and cost-effective when compared to other remediation technologies. In the present study, distinct strategies will be used for detoxification/degradation of soils contaminated with diesel oil (natural attenuation, bioaugmentation, and biostimulation), in order to select the best conditions of bioremediation for this pollutant. It will be evaluated a microbial consortium composed by marine fungi, bacteria from oil reservoir (off-shore), and yeast from Antartic, which was able to detoxify efficiently the diesel oil after 21 days of submerged cultivation in previous studies. The diesel oil degradation in the distinct treatments will be monitored through gas chromatography, while the detoxification will be performed by acute toxicity analysis with Microtox (Vibrio fisheri) and the microcrustacean Artemia sp. This project aims to elucidate the complex microbial mechanisms involved in the diesel oil detoxification/degradation (in the selected treatment) by metatranscriptome, as well as monitor the dynamics of the microbial community during the detoxification/degradation process using genetic fingerprinting (PCD-DGGE). The access to the taxonomic profile of the microorganisms involved in the detoxification/degradation process will be carry out by cloning and sequencing. (AU)