Potencial biotecnológico de bactérias isoladas a partir de consórcios provenientes de água de produção em reservatórios de petróleo no Brasil

Abstract

During the oil and gas extractive processes, production water is also formed, which is composed of organic and inorganic matter, in addition to microorganisms. The microbiota of this environment, adapted to extreme conditions, has great potential for application in biotechnological processes, such as bioremediation and/or MEOR (Microbial Enhance Oil Recovery). Within this context, this study aimed at the isolation, identification and characterization of bacteria from three consortia, previously obtained from production water. A total of 16 bacteria were isolated, fifteen of which were selected for metabolic characterization from functional assays. The isolates were selected according to their ability to use hydrocarbons as a carbon source. For this, growth curves were prepared using minimal medium supplemented with petroleum as the only carbon source. Considering the degradation of hydrocarbons, the test with redox indicator 2,6 - DCPIP (2,6- Dichlorophenolindophenol) was used and tests such as Emulsification Index, droplet collapse and oil dispersion were applied to evaluate the production of biosurfactants/ bioemulsifiers. The results obtained from the degradation tests confirmed the ability of fifteen isolates to use oil and other hydrocarbons as the only carbon source. The tests carried out for the production of biosurfactants confirmed the ability of these isolates to produce biosurfactants and/or form an emulsion. Based on the 16S gene sequence, the isolates were identified as belonging to the genera Bacillus pumillus/safensis, Acinetobacter baumanii, Staphylococcus cohnii, Ochrobactrum sp. and Citrobacter amalonaticus. Among the isolates, four were selected and had their genomes sequenced, being identified as Bacillus safeensis (2), Ochrobactrum (1) and Acinetobacter baumanii (1). The isolate AP1BH01-1, classified as a member of the genus Ochrobactrum, was designated as a new species, since it does not group with another species of the genus. The genomes of the sequenced isolates showed a great diversity of genes whose products are involved in the degradation of aliphatic and aromatic hydrocarbons, as well as genes encoding proteins involved in the synthesis of biosurfactants and bioemulsifiers. Several genes related to products that confer resistance to heavy metals were also identified. The data obtained through functional assays and genome mining of the isolates revealed promising profiles in hydrocarbon degradation processes and production of biosurfactants for application in bioremediation of environments contaminated with hydrocarbons and/or application in MEOR to improve extraction in mature wells.