Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater

Ulrich, Ania C.; Guigard, Selma E.; Foght, Julia M.; Semple, Kathleen M.; Pooley, Kathryn; Armstrong, James E.; Biggar, Kevin W.

doi:10.1007/s10532-008-9196-0

Cited by 47 publications

(24 citation statements)

References 20 publications

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“…The phenanthrene peak area was compared to the peak of oterphenyl, which served as both an extraction and surrogate standard for phenanthrene quantification. Mineralization and transformation of radiolabeled phenanthrene and glucose Mineralization and metabolite production by P. fluorescens strains WEP, WEN, NEP, and NEN, incubated with radiolabeled substrates, were measured as cumulative 14 CO 2 evolution and 14 C-water-soluble products as described by Ulrich et al (2009). Experiments were performed using biometer flasks containing 25 ml BH medium, 250 mg l −1 12 C-phenanthrene or 0.1% 12 C-glucose, 0.5 mM 2-aminobenzoate, and 25 μl of inoculum suspension (OD 600 03.0).…”

Section: Phenanthrene Biodegradation Assaymentioning

confidence: 99%

“…Abiotic (no cells) and killed cell (heat-killed WEP cells) controls were also performed using the same method as single cultures to account for radiolabel sorption to glassware and partitioning into cells, respectively. Cumulative 14 CO 2 trapped in the KOH in the side arm of biometer flasks was measured as described by Ulrich et al (2009). Water-soluble phenanthrene metabolites were measured in supernatant samples from the culture medium as follows: at intervals, 1-ml culture samples were collected and centrifuged at 13,000×g for 10 min to remove insoluble residual 14 C-phenanthrene and cells.…”

Section: Phenanthrene Biodegradation Assaymentioning

confidence: 99%

“…The efficiency of PAH biodegradation depends on environmental factors such as the bioavailability of the substrate (Cerniglia 1992), temperature, pH, and salinity (Ulrich et al 2009) and cell properties such as adhesion to hydrocarbons (Abbasnezhad et al 2011a, b), but the effect of efflux on the efficiency of PAH biodegradation has not been studied previously. Because the efflux of a substrate may reduce its availability for catabolism by cytoplasmic enzymes, we hypothesized that phenanthrene biodegradation would be greater in an emhB mutant than in the wild type.…”

Section: Introductionmentioning

confidence: 99%

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The EmhABC efflux pump decreases the efficiency of phenanthrene biodegradation by Pseudomonas fluorescens strain LP6a

Adebusuyi

Smith

Gray

et al. 2012

Appl Microbiol Biotechnol

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Pseudomonas fluorescens strain LP6a, designated here as strain WEN (wild-type PAH catabolism, efflux positive), utilizes the polycyclic aromatic hydrocarbon phenanthrene as a carbon source but also extrudes it into the extracellular medium using the efflux pump EmhABC. Because phenanthrene is considered a nontoxic carbon source for P. fluorescens WEP, its energy-dependent efflux seems counter-productive. We hypothesized that the efflux of phenanthrene would decrease the efficiency of its biodegradation. Indeed, an emhB disruptant strain, wild-type PAH catabolism, efflux negative (WEN), biodegraded 44% more phenanthrene than its parent strain WEP during a 6-day incubation. To determine whether efflux affected the degree of oxidation of phenanthrene, we quantified the conversion of ¹⁴C-phenanthrene to radiolabeled polar metabolites and ¹⁴CO₂. The emhB⁻ WEN strain produced approximately twice as much ¹⁴CO₂ and radiolabeled water-soluble metabolites as the WEP strain. In contrast, the mineralization of ¹⁴C-glucose, which is not a known EmhB efflux substrate, was equivalent in both strains. An early open-ring metabolite of phenanthrene, trans-4-(1-hydroxynaphth-2-yl)-2-oxo-3-butenoic acid, also was found to be a substrate of the EmhABC pump and accumulated in the supernatant of WEP but not WEN cultures. The analogous open-ring metabolite of dibenzothiophene, a heterocyclic analog of phenanthrene, was extruded by EmhABC plus a putative alternative efflux pump, whereas the end product 3-hydroxy-2-formylbenzothiophene was not actively extruded from either WEP or WEN cells. These results indicate that the active efflux of phenanthrene and its early metabolite(s) decreases the efficiency of phenanthrene degradation by the WEP strain. This activity has implications for the bioremediation and biocatalytic transformation of polycyclic aromatic hydrocarbons and heterocycles.

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Section: Phenanthrene Biodegradation Assaymentioning

confidence: 99%

Section: Phenanthrene Biodegradation Assaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The EmhABC efflux pump decreases the efficiency of phenanthrene biodegradation by Pseudomonas fluorescens strain LP6a

Adebusuyi

Smith

Gray

et al. 2012

Appl Microbiol Biotechnol

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“…Two hundred and fifty microliters of HMN containing [9-14 C]phenanthrene plus unlabelled phenanthrene was added to each culture at time zero, giving the desired phenanthrene concentration and *100,000 disintegrations per minute (dpm). Cumulative 14 CO 2 production was measured as previously described (Ulrich et al 2009). At intervals, 0.7-ml samples of culture were removed and clarified at 13,0009g in a microfuge.…”

Section: Mineralization Experimentsmentioning

confidence: 99%

Adhesion to the hydrocarbon phase increases phenanthrene degradation by Pseudomonas fluorescens LP6a

2010

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Microbial adhesion is an important factor that can influence biodegradation of poorly water soluble hydrocarbons such as phenanthrene. This study examined how adhesion to an oil-water interface, as mediated by 1-dodecanol, enhanced phenanthrene biodegradation by Pseudomonas fluorescens LP6a. Phenanthrene was dissolved in heptamethylnonane and added to the aerobic aqueous growth medium to form a two phase mixture. 1-Dodecanol was non-toxic and furthermore could be biodegraded slowly by this strain. The alcohol promoted adhesion of the bacterial cells to the oil-water interface without significantly changing the interfacial or surface tension. Introducing 1-dodecanol at concentrations from 217 to 4,100 mg l(-1) increased phenanthrene biodegradation by about 30% after 120 h incubation. After 100 h incubation, cultures initially containing 120 or 160 mg l(-1) 1-dodecanol had mineralized >10% of the phenanthrene whereas those incubated without 1-dodecanol had mineralized only 4.5%. The production and accumulation of putative phenanthrene metabolites in the aqueous phase of cultures likewise increased in response to the addition of 1-dodecanol. The results suggest that enhanced adhesion of bacterial cells to the oil-water interface was the main factor responsible for enhanced biodegradation of phenanthrene to presumed polar metabolites and to CO(2).

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“…Hydrocarbonoclastic activity in non-saline soils (MinaiTehrani et al 2006(MinaiTehrani et al , 2009Rhykerd et al 1995) and groundwater (Ulrich et al 2009) by microorganisms is impaired when salinity increases (Huyop et al 2000;Lay et al 2010). In such environments, the ability of microbial communities to degrade hydrocarbons is expected to decrease because they are not adapted to saline (Margesin and Schinner 2001).…”

Section: Microbial Degradation Of Hydrocarbon Pollutants In Hypersalimentioning

confidence: 99%

Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments

Edbeib

Wahab

Huyop

2016

World J Microbiol Biotechnol

138

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The unique cellular enzymatic machinery of halophilic microbes allows them to thrive in extreme saline environments. That these microorganisms can prosper in hypersaline environments has been correlated with the elevated acidic amino acid content in their proteins, which increase the negative protein surface potential. Because these microorganisms effectively use hydrocarbons as their sole carbon and energy sources, they may prove to be valuable bioremediation agents for the treatment of saline effluents and hypersaline waters contaminated with toxic compounds that are resistant to degradation. This review highlights the various strategies adopted by halophiles to compensate for their saline surroundings and includes descriptions of recent studies that have used these microorganisms for bioremediation of environments contaminated by petroleum hydrocarbons. The known halotolerant dehalogenase-producing microbes, their dehalogenation mechanisms, and how their proteins are stabilized is also reviewed. In view of their robustness in saline environments, efforts to document their full potential regarding remediation of contaminated hypersaline ecosystems merits further exploration.

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Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater

Cited by 47 publications

References 20 publications

The EmhABC efflux pump decreases the efficiency of phenanthrene biodegradation by Pseudomonas fluorescens strain LP6a

The EmhABC efflux pump decreases the efficiency of phenanthrene biodegradation by Pseudomonas fluorescens strain LP6a

Adhesion to the hydrocarbon phase increases phenanthrene degradation by Pseudomonas fluorescens LP6a

Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments

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