Publicação
Biotech strategies to improve the quality of crude oils
| Resumo: | The isolation and identification of microorganisms with potential for bioconversion in petroleum fields is of great relevance, since these organisms may be related to a decrease in petroleum quality in the reservoirs or cause damages in the production facilities; furthermore, microorganisms with beneficial effects and activities can also be found. In that sense, a petroleum sample was obtained from a Brazilian oil field (oil well CLB), with the aim of isolating microorganisms and evaluating their ability to degrade different hydrocarbons, in particular long chain n-alkanes. Twenty-three isolates were obtained from the oil sample: fourteen bacterial isolates and nine filamentous fungi. Five isolates were identified as Pseudomonas sp. according to their macroscopic characteristics. The Pseudomonas sp. strains were selected due to their high biosurfactant-producing ability. The biosurfactants produced by those isolates reduced the surface tension of water from 72 to 30 mN/m, and exhibited emulsifying activities of almost 60%. Furthermore, one of the filamentous fungi isolated, identified through morphological and molecular techniques as Scedosporium spp., produced a bioemulsifier growing in a medium containing 30% (v/v) of oil mill wastewater (OMW). This bioemulsifier exhibited high stability at extreme conditions of pH and salinity. Oil treatments using microorganisms to improve the API degree of heavy crude oils constitute an innovative approach. In that sense, the Mukhaizna crude oil (heavy oil) was subjected to treatments with filamentous fungi, Pseudomonas sp. and Bacillus subtilis strains, all of them isolated from oil samples. However, none of the assays performed improved the quality of this oil. Other promising biotechnological application is Microbial Enhanced Oil Recovery (MEOR), which is potentially useful to increment oil recovery from reservoirs beyond primary and secondary recovery operations using microorganisms and their metabolites. In this work, a sand-pack column model was used to simulate the oil recovery operations and evaluate the mobilization of residual oil by three filamentous fungi isolated from the oil sample, with additional oil recoveries ranging from 1.9 to 9.2%. In conclusion, although the main objective of this work couldn’t be achieved (improve the quality of Mukhaizna crude oil), the results obtained show that microorganisms isolated from oil reservoirs can be useful for several applications, not only in the oil industry, but also in other areas such as waste management and the production of surface-active compounds for several applications. |
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| Autores principais: | Quintinha, Soraia Milene Oliveira |
| Assunto: | Engenharia e Tecnologia::Biotecnologia Industrial |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The isolation and identification of microorganisms with potential for bioconversion in petroleum fields is of great relevance, since these organisms may be related to a decrease in petroleum quality in the reservoirs or cause damages in the production facilities; furthermore, microorganisms with beneficial effects and activities can also be found. In that sense, a petroleum sample was obtained from a Brazilian oil field (oil well CLB), with the aim of isolating microorganisms and evaluating their ability to degrade different hydrocarbons, in particular long chain n-alkanes. Twenty-three isolates were obtained from the oil sample: fourteen bacterial isolates and nine filamentous fungi. Five isolates were identified as Pseudomonas sp. according to their macroscopic characteristics. The Pseudomonas sp. strains were selected due to their high biosurfactant-producing ability. The biosurfactants produced by those isolates reduced the surface tension of water from 72 to 30 mN/m, and exhibited emulsifying activities of almost 60%. Furthermore, one of the filamentous fungi isolated, identified through morphological and molecular techniques as Scedosporium spp., produced a bioemulsifier growing in a medium containing 30% (v/v) of oil mill wastewater (OMW). This bioemulsifier exhibited high stability at extreme conditions of pH and salinity. Oil treatments using microorganisms to improve the API degree of heavy crude oils constitute an innovative approach. In that sense, the Mukhaizna crude oil (heavy oil) was subjected to treatments with filamentous fungi, Pseudomonas sp. and Bacillus subtilis strains, all of them isolated from oil samples. However, none of the assays performed improved the quality of this oil. Other promising biotechnological application is Microbial Enhanced Oil Recovery (MEOR), which is potentially useful to increment oil recovery from reservoirs beyond primary and secondary recovery operations using microorganisms and their metabolites. In this work, a sand-pack column model was used to simulate the oil recovery operations and evaluate the mobilization of residual oil by three filamentous fungi isolated from the oil sample, with additional oil recoveries ranging from 1.9 to 9.2%. In conclusion, although the main objective of this work couldn’t be achieved (improve the quality of Mukhaizna crude oil), the results obtained show that microorganisms isolated from oil reservoirs can be useful for several applications, not only in the oil industry, but also in other areas such as waste management and the production of surface-active compounds for several applications. |
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