Development of novel bacterial consortium for biodegradation of paraffin wax in crude oil
The deposition of paraffin wax in crude oil is a problem faced by the oil and gas industry during the extraction, transportation, and refining of crude oil. Millions of dollars were spent annually to control wax deposition in the pipeline. As an alternative to prevent wax deposition, this study a...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/97752/1/FBSB%202021%203%20UPMIR.pdf |
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| Summary: | The deposition of paraffin wax in crude oil is a problem faced by the oil and gas
industry during the extraction, transportation, and refining of crude oil. Millions
of dollars were spent annually to control wax deposition in the pipeline. As an
alternative to prevent wax deposition, this study aimed to develop a novel
bacterial consortium for the biodegradation of paraffin wax in crude oil. Eleven
paraffin wax degrading bacteria were screened at 70 °C using crude oil B and
these isolates showed the ability to degrade the crude oil. The medium for
bacterial growth and degradation was optimized with yeast extract alone to
enhance the biodegradation of crude oil. The 16S rRNA gene identification of
isolates revealed that these isolates are Geobacillus kaustophilus strain N3A7,
Geobacillus kaustophilus strain NFA23, Geobacillus kaustophilus strain DFY1,
Parageobacillus caldoxylosilyticus strain DFY3, Parageobacillus
caldoxylosilyticus strain AZ72, Geobacillus jurassicus strain MK7,
Anoxybacillus geothermalis strain D9 (previously identified), Geobacillus
thermocatenulatus strain T7, Geobacillus stearothermophilus strain SA36,
Geobacillus stearothermophilus strain AD24, and Geobacillus
stearothermophilus strain AD11. Gas chromatography-mass spectrometry
(GCMS) analysis of residual hydrocarbon showed more than 70%
biodegradation efficiency by strains AD11, DFY1, AD24, N3A7, and MK7
compared to other strains. The degradative alkane monooxygenase enzyme
activity of strain AD24 was the highest. Strains N3A7, MK7, DFY1, AD11, and
AD24 (high degraders) also demonstrated relatively higher alcohol
dehydrogenase, lipase, and esterase activity compared to other strains. Five
consortia were developed based on the biodegradation efficiency of 11
bacterial strains. Consortium 3 (77.8%) showed the highest biodegradation with
more long-chain alkane degraded throughout the incubation compared to other
consortia. The degradation of long-chain alkane (paraffin wax) by all consortia
also caused an increase of short-chain alkanes contents. Consortium 3 also
exhibited higher alkane monooxygenase, alcohol dehydrogenase, lipase, and
esterase activity compared to other consortia. The dominant bacteria in the consortia were identified by denaturing gradient gel electrophoresis (DGGE).
The results showed that P. caldoxylosilyticus strain DFY3, P. caldoxylosilyticus
strain AZ72, and G. kaustophilus strain N3A7 were dominant in consortium 1,
consortium 2, and consortium 3, respectively throughout the incubation. In
consortium 4, P. caldoxylosilyticus strain DFY3, G. thermocatenulatus strain
T7, and G. stearothermophilus strain SA36 were dominant on different days of
incubation. Consortium 5 also showed the dominance of G. kaustophilus sp.
and G. stearothermophilus sp. on different days of incubation. In conclusion,
the bacterial consortia showed improvement in degrading more long-chain
hydrocarbons while increasing some short-chain hydrocarbons. This
improvement could lower oil viscosity and reduce oil production loss |
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