Effect of the dispersant Corexit 9527 on the microbial degradation of sulfur heterocycles in Prudhoe Bay oil

Samples from a previous study observing the effects of Corexit 9527 on microbial degradation of aromatics and saturates in crude oil were reanalyzed by capillary gas chromatography with a sulfur-specific detector. The results show an inhibitory effect on degradation of sulfur heterocycles (such as benzothiophenes and dibenzothiophenes), dependent upon dispersant concentration and nutrient supplementation.

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Microbial degradation of organic sulfur compounds in Prudhoe Bay crude oil

Canadian Journal of Microbiology ◽

10.1139/m83-048 ◽

1983 ◽

Vol 29 (3) ◽

pp. 291-296 ◽

Cited By ~ 36

Author(s):

P. M. Fedorak ◽

D. W. S. Westlake

Keyword(s):

Crude Oil ◽

Microbial Population ◽

Sulfur Compounds ◽

Residual Oil ◽

Nutrient Supplementation ◽

Organic Sulfur Compounds ◽

Sulfur Heterocycles ◽

Prudhoe Bay ◽

Oil Tanker ◽

Two Populations

Water samples from three different marine environments in Washington State were challenged with Prudhoe Bay crude oil and incubated at 8 °C with aeration. Some cultures were supplemented with NH4NO3 and phosphate and after various lengths of time, up to 27 days, the residual oil was extracted and fractionated using silica gel columns. The aromatic fraction was analyzed by capillary gas chromatography using a sulfur-specific flame photometric detector. The oil contained alkylbenzo[b]thiophenes, dibenzothiophene, and C1- and C2-dibenzothiophenes and the degradation of these was monitored. Many of the sulfur heterocycles were metabolized without nutrient supplementation although the number and extent of the compounds degraded increased with nutrient addition. The order of susceptibility of the sulfur heterocycles in homologous series was found to be the following: C2-benzo[b]thiophenes > C3-benzothiophenes; dibenzothiophene > C1-dibenzothiophenes > C2-dibenzothiophenes. With nutrient supplementation, the microbial population from a harbor area metabolized the sulfur compounds more readily than those from near an oil tanker dock or from a pristine state park beach. Without supplementation, the population from the tanker dock area degraded many fewer sulfur heterocycles than the other two populations.

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Microbial degradation of aromatics and saturates in Prudhoe Bay crude oil as determined by glass capillary gas chromatography

Canadian Journal of Microbiology ◽

10.1139/m81-066 ◽

1981 ◽

Vol 27 (4) ◽

pp. 432-443 ◽

Cited By ~ 83

Author(s):

P. M. Fedorak ◽

D. W. S. Westlake

Keyword(s):

Gas Chromatography ◽

Crude Oil ◽

Capillary Gas Chromatography ◽

Time Course ◽

Glass Capillary ◽

Nitrogen And Phosphorus ◽

Complex Molecules ◽

Pristine Area ◽

Prudhoe Bay ◽

Oil Tanker

Water samples obtained from three different marine environments (including a commercial harbor, a pristine area, and an oil tanker dock area) from the coast of Washington State were challenged with Prudhoe Bay crude oil under shake-flask conditions at 8 °C. Replicate cultures were grown with and without nitrogen (NO3−, NH4+) and phosphate supplementation. After varying incubation periods, the residual oil was extracted and separated on silica gel columns into saturate and aromatic fractions and these were analyzed by glass capillary gas chromatography to detect the degradation of various compounds. After 27 days of incubation, both the aromatic and saturate fractions were extensively degraded by the microorganisms from these environments when supplemented with nitrogen and phosphorus. Without nutrient supplementation, the aromatics were more readily attacked than the saturates by the populations from the pristine environment and from the commercial harbor area. Under these limited nutrient conditions, samples from near oil tanker docks showed moderate degradation of both the saturate and aromatic fractions. Time course studies, using nutrient-supplemented marine samples, showed that the simple aromatics (e.g., naphthalene and 2-methylnaphthalene) were more readily degraded than the n-alkanes. However, once the breakdown of these saturates commenced, these were quickly removed from the oil. The aromatic degradation continued to progress from lower molecular weight, less complex molecules to larger, more complex molecules in the approximate series C2 naphthalenes; phenanthrene and dibenzothiophene; C3 naphthalenes and methylphenathrenes; C2 phenanthrenes.

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Microbial Degradation Of Normal Paraffin Hydrocarbons In Crude Oil

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1969-1-327 ◽

1969 ◽

Vol 1969 (1) ◽

pp. 327-331 ◽

Cited By ~ 7

Author(s):

R.J. Miget ◽

C.H. Oppenheimer ◽

H.I. Kator ◽

P.A. LaRock

Keyword(s):

Surface Tension ◽

Gas Chromatography ◽

Crude Oil ◽

Microbial Degradation ◽

Oil Degradation ◽

Marine Microorganisms ◽

Normal Paraffin ◽

Naturally Occurring ◽

Enriched Cultures ◽

Micro Organisms

Abstract Experiments designed to measure the oxidation and degradation of crude oils by naturally occurring marine microorganisms are presently being conducted. Fifty active oil degrading cultures have been isolated in enriched seawater containing crude oil. Oil degradation has been determined with gas chromatography, wet combustion, and by measurement of surface tension. Normal paraffin hydrocarbons through C-26 are degraded by two different groups of micro organisms-those growing in the oil phase only and those growing in the aqueous phase. Emulsification of the crude oil through production of surfactants was observed in many of the enriched cultures. Microbial degradation of 35 to 55 per cent of oxidizable crude oil occurred within 60 hours.

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Effect of the dispersant Corexit 9527 on the microbial degradation of Prudhoe Bay oil

Canadian Journal of Microbiology ◽

10.1139/m82-012 ◽

1982 ◽

Vol 28 (1) ◽

pp. 117-122 ◽

Cited By ~ 26

Author(s):

J. M. Foght ◽

D. W. S. Westlake

Keyword(s):

Crude Oil ◽

Microbial Degradation ◽

Incubation Time ◽

Phosphate Solution ◽

Alkane Degradation ◽

Marine Oil ◽

Aromatic Fraction ◽

Substrate Degradation ◽

Selective Sensitivity ◽

Prudhoe Bay

A marine oil-degrading population grown at 8 °C showed a selective sensitivity regarding utilization of compounds in Prudhoe Bay oil in the presence of the dispersant Corexit 9527. The response was dependent on the nitrogen and phosphate levels of the medium and on the concentration of dispersant used. In the presence of a nitrogen–phosphate solution and a Corexit 9527 – crude oil substrate, degradation of the n-alkanes of the saturate fraction was temporarily retarded in proportion to the concentration of Corexit 9527 present. This retardation was overcome with extended incubation time. In the absence of nitrogen–phosphate supplementation, the effect of Corexit 9527 was pronounced, retarding n-alkane degradation even with extended incubation time. Corexit 9527 had less effect on the degradation of the aromatic fraction and may indeed be stimulatory in the case of select compounds. The development and testing of dispersants containing nitrogen and phosphate is recommended.

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