Sinergismo entre cepas de um consórcio bacteriano degradador de diesel isolado do Rio Negro

Abstract

Over the last few decades, pollution caused by hydrocarbons has been reported as one of the main environmental problems in the world. The sources of hydrocarbon contamination are as varied as possible, such as oil leaks, underground fuel tank leaks, waters contaminated by the production of oil and gas, among others. These activities can cause serious environmental and economic problems for terrestrial and marine ecosystems. The effects of these activities depend on the level of contamination, location of the accident and, above all, the environmental conditions at the time o the accident. Diesel is a fuel derived from oil and is among the most consumed of all fuels. In the Amazon region, its consumption is certainly higher due to the large amount of vessels powered by diesel oil, which can be an aggravating factor for environmental problems in the region. Alternatives that are able to promote the degradation of hydrocarbons, without further aggravating the environmental problem, is of extreme importance in the current scenario. Among the most used techniques in this decontamination process, bioremediation has gained prominence. There is, however, a consensus in the literature that no microorganism has the capacity to fully metabolize oil. Hence, the constant search for the isolation of consortia that promote the degradation of a greater amount of xenobiotics present in oil and its derivatives. Therefore, the objective of this work was to select a bacterial consortium capable of effectively degrading hydrocarbons present in diesel and then make a proteomic analysis of this selected bacterial consortium. The consortia were collected in the vicinity of the Port of Ceasa in the city of Manaus, Brazil. In total 5, consortia were collected, and all of them were able to use diesel as a carbon source, especially A3, which was superior to the others. The results presented for this consortium were the best for DCPIP reduction, emulsification (in xylene, hexane and diesel), cellular hydrophobicity (in xylene, hexane and diesel), diesel solubilization and in the toxicity test with L. sativa. The diesel degradation rate by the A3 consortium, in just 7 days, was higher than 70%. From the analysis of the proteome of this consortium, 890 proteins were identified. These proteins all belong to the species Acinetobacter baumannii, Burkholderia cenocepacia and Cupriavidus taiwanensis. Evidence was found for the degradation of 11 xenobiotic compounds present in diesel, distributed between aliphatic and aromatic compounds. The detailed analysis of the participation of proteins identified in the metabolic routes used by each species, enabled the proposition of a synergistic action between the three strains that make up the A3 consortium for the metabolism of diesel. Thus, the A3 consortium has a huge potential for the recovery of areas affected by diesel or other petroleum hydrocarbons.