Caracterização da microbiota de uma amostra de petróleo do pré-sal

• Ano de defesa: 2019
• Autor(a) principal: Freitas, Júlia Firme
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM BIOQUÍMICA
• Palavras-chave em Português: Consórcio; Metagenômica; Petróleo; Microrganismos; Biodegradação; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/28015

Petroleum is one of the world's main source of energy. On Brazil pre-salt reservoir discovery and extraction has boosted oil production. However, such activity generates recurrent environmental contaminations, causing global problems. Microorganisms demonstrate the ability to degrade oil, so microbial metabolism can provide an opportunity to bioremediate contaminated environments and assist in reservoir management, contributing to maintenance oil quality or oil recovery. Identification of the microbiota in the reservoir provides data to understand the metabolism of oil degradation. It is worth mentioning that there are still no pre-salt microbiota analyzes, described in the literature, by dependent or independent culture approaches. The objective of this work was to obtain and characterize isolates and microbial consortia (indefinite and definite) capable of degrading petroleum. From a pre-salt oil sample three indefinite consortia and 26 isolates were obtained. To evaluate the potentials of the consortia and isolates, the following tests were performed: i) oil degradation ability, ii) production of biosurfactants; iii) cellular hydrophobicity; iv) biofilm production; v) enzymatic activity of hydroxylases; vi) presence of rhamnolipid and vii) growth curve. All isolates demonstrated the ability to degrade petroleum and some by-products by the DCPIP test, 46% used kerosene and 7% degraded xylene and toluene. The oil dispersion test showed that all isolates produce biosurfactants, yet 22 to emulsify kerosene. Lipase was produced by all isolates, however, only 4 strains produced esterase. The isolates were identified as belonging to the genera Bacillus (n= 9), Ochrobactrum (n = 11), Acinetobacter (n=2), Dermacoccus (n=1) e Staphylococcus (n = 2). One definite consortium was elaborated with eleven isolates that presented the best results in the functional tests. The estimation of degradation indicate that all consortia degraded 100% of oil, diesel, gasoline, soybean oil, olive oil and hexadecane, while degradation of kerosene was 46 to 90%, xylene 44 to 77% and toluene 43 to 78%; the emulsification index of the consortia ≥58%. The comparison of the results between the selected and the indefinite consortia shows similarities in the functional characteristics (growth curve, hydrocarbon degradation and biosurfactant production). It is concluded that microorganisms obtained from or enriched by petroleum have the ability to degrade oil from biofilm production and cell hydrophobicity modification, and the selected consortium presents the same potential of the native microbiota, being a good possibility for application of bioremediation; while indefinite consortia can provide data for reservoir management.