Prospecção na comunidade bacteriana degradadora de hidrocarbonetos de petróleo em sedimento marinho costeiro submerso no litoral do Ceará

Abstract

Coastal environments are routinely impacted by human activities and, in particular, those linked to the petrochemical industry. In Brazil, among the dramatic events recorded related to oil spills at sea in 2019, there was what was considered the most serious environmental disaster in tropical waters that mainly affected the coast of the northeast region. Petroleum, in addition to other compounds, is made up of hydrocarbons that can be considered pollutants that persist in the environment, which accumulate in sediments and soil, have low solubility, are hydrophobic and, because they have these characteristics, are difficult to biodegrade. However, there are microorganisms, such as hydrocarbonoclastic bacteria, capable of efficiently degrading hydrocarbons, being studied as potential bioremediation agents in areas affected by oil spills. Considering this bacterial capacity, the general objective of this research was to analyze the hydrocarbon-degrading microbiota in the marine sediment in areas affected by the 2019 oil spill on the coast of Ceará. The methodology applied consisted of collecting submerged marine sediment in areas affected by the 2019 oil spill for the isolation and cultivation of bacterial strains, selection of strains with the potential to degrade hydrocarbons (drop collapse and antagonism test), consortium efficiency test free bacteria, inoculum of bacterial isolates in microcosms to monitor oil degradation through chromatography and genotypic identification of hydrocarbonoclastic bacteria isolated from the sediment on the coast of Ceará. As a result, 180 strains were isolated, 26 consortia were assembled and 4 were applied to the efficiency test. In the hydrocarbon degradation test, 2 consortia were used and a decrease in the concentration of total aliphatic hydrocarbons was found from 42% to 97% over 15 days. On the other hand, an increase in the concentration of low molecular weight aliphatic alkanes was also observed. Using molecular biology, it was possible to verify that the isolates used in the consortia are part of the hydrocarbonoclastic group of bacteria. Therefore, free bacterial consortia assembled from microbiota isolated from marine sediment impacted by oil were capable of degrading aliphatic petroleum hydrocarbons and have a potential for bioremediation of areas impacted by hydrophobic compounds.