Rhizosphere microbial populations in contaminated soils

Nichols, Thomas D.; Wolf, D. C.; Rogers, H. B.; Beyrouty, C. A.; Reynolds, C. M.

doi:10.1007/bf02406163

Cited by 131 publications

(76 citation statements)

References 27 publications

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“…Numerous studies have demonstrated the importance of the rhizosphere effect on degradation of organic contaminants. Most of these studies have examined terrestrial plants and agricultural chemicals (1,2,27); few have looked at the influence of plant-associated microorganisms on the fate of PCBs (15,16) and PAHs (34,39). There have been a limited number of studies on PAH degradation involving wetland or salt marsh ecosystems, but none have studied the diversity of PAH-degrading microorganisms present (28,30,49).…”

Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants

Daane¹,

Harjono²,

Zylstra

et al. 2001

Appl Environ Microbiol

271

122

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Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were isolated from contaminated estuarine sediment and salt marsh rhizosphere by enrichment using either naphthalene, phenanthrene, or biphenyl as the sole source of carbon and energy. Pasteurization of samples prior to enrichment resulted in isolation of gram-positive, spore-forming bacteria. The isolates were characterized using a variety of phenotypic, morphologic, and molecular properties. Identification of the isolates based on their fatty acid profiles and partial 16S rRNA gene sequences assigned them to three main bacterial groups: gram-negative pseudomonads; grampositive, non-spore-forming nocardioforms; and the gram-positive, spore-forming group, Paenibacillus. Genomic digest patterns of all isolates were used to determine unique isolates, and representatives from each bacterial group were chosen for further investigation. Southern hybridization was performed using genes for PAH degradation from Pseudomonas putida NCIB 9816-4, Comamonas testosteroni GZ42, Sphingomonas yanoikuyae B1, and Mycobacterium sp. strain PY01. None of the isolates from the three groups showed homology to the B1 genes, only two nocardioform isolates showed homology to the PY01 genes, and only members of the pseudomonad group showed homology to the NCIB 9816-4 or GZ42 probes. The Paenibacillus isolates showed no homology to any of the tested gene probes, indicating the possibility of novel genes for PAH degradation. Pure culture substrate utilization experiments using several selected isolates from each of the three groups showed that the phenanthrene-enriched isolates are able to utilize a greater number of PAHs than are the naphthalene-enriched isolates. Inoculating two of the gram-positive isolates to a marine sediment slurry spiked with a mixture of PAHs (naphthalene, fluorene, phenanthrene, and pyrene) and biphenyl resulted in rapid transformation of pyrene, in addition to the two-and three-ringed PAHs and biphenyl. This study indicates that the rhizosphere of salt marsh plants contains a diverse population of PAH-degrading bacteria, and the use of plant-associated microorganisms has the potential for bioremediation of contaminated sediments.

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Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants

Daane¹,

Harjono²,

Zylstra

et al. 2001

Appl Environ Microbiol

271

122

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“…At higher TPH concentrations microbes have a faster metabolic rate due to the presence of excess carbon as a food source (Nichols et al, 1996). This high level of metabolic activity may have influenced the numbers of microbes catalogued in this experiment in two ways.…”

Section: Discussionmentioning

confidence: 99%

Phytoremediation of hydrocarbon contaminants in subantarctic soils: An effective management option

Bramley-Alves

Wasley

King

et al. 2014

Journal of Environmental Management

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Accidental fuel spills on world heritage subantarctic Macquarie Island have caused considerable contamination. Due to the island's high latitude position, its climate, and its fragile ecosystem, traditional methods of remediation are unsuitable for on-site clean up. We investigated the tolerance of a subantarctic native tussock grass, Poa foliosa (Hook. f.), to Special Antarctic Blend (SAB) diesel fuel and its potential to reduce SAB fuel contamination via phytoremediation. Toxicity of SAB fuel to P. foliosa was assessed in an 8 month laboratory growth trial under growth conditions which simulated the island's environment. Single seedlings were planted into 1 L pots of soil spiked with SAB fuel at concentrations of 1000, 5 000, 10 000, 2000 and 40 000 mg/kg (plus control). Plants were harvested at 0, 2, 4 and 8 months and a range of plant productivity endpoints were measured (biomass production, plant morphology and photosynthetic efficiency). Poa foliosa was highly tolerant across all SAB fuel concentrations tested with respect to biomass, although higher concentrations of 20 000 and 40 000 mg SAB/kg soil caused slight reductions in leaf length, width and area. To assess the phytoremediation potential of P. foliosa (to 10 000 mg/kg), soil from the planted pots was compared with that from paired unplanted pots at each SAB fuel concentration. The effect of the plant on SAB fuel concentrations and the associated microbial communities found within the soil (total heterotrophs and hydrocarbon degraders) were compared between planted and unplanted treatments at the 0, 2, 4 and 8 month harvest periods. The presence of plants resulted in significantly less SAB fuel in soils at 2 months and a return to background concentration by 8 months. Microbes did not appear to be the sole driving force behind the observed hydrocarbon loss. This study provides evidence that phytoremediation using P. foliosa is a valuable remediation option for use at Macquarie Island, and may be applicable to the management of fuel spills in other cold climate regions. AbstractAccidental fuel spills on world heritage subantarctic Macquarie Island have caused considerable contamination. Due to the island's high latitude position, its climate, and its fragile ecosystem, traditional methods of remediation are unsuitable for on-site clean up. We investigated the tolerance of a subantarctic native tussock grass, Poa foliosa (Hook. f.), to Special Antarctic Blend (SAB) diesel fuel and its potential to reduce SAB fuel contamination via phytoremediation. Toxicity of SAB fuel to P. foliosa was assessed in an 8 month laboratory growth trial under growth conditions which simulated the island's environment. Single seedlings were planted into 1 L pots of soil spiked with SAB fuel at concentrations of 1 000, 5 000, 10 000, 20 00 and 40 000 mg/kg (plus control). Plants were harvested at 0, 2, 4 and 8 months and a range of plant productivity endpoints were measured (biomass production, plant morphology and photosynthetic efficiency). Poa foliosa was highl...

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“…Various grasses and leguminous crops were used for rhizoremediation because of the profound root biomass [7]. The establishment of crop cover also improves the soil physical and chemical properties of contaminated soil and increase the contact microbes and contaminants [15].…”

Section: Introductionmentioning

confidence: 99%

Rhizoremediation of metals: harnessing microbial communities

Banu

Ramasamy

2008

Indian J Microbiol

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With the increasing successful stories of decontamination, different strategies for metal remediation are gaining importance and popularization in developing countries. Rhizoremediation, is one such promising option that harnesses the impressive capabilities of microorganisms associated with roots to degrade organic pollutants and transform toxic metals. Since it is a plant based in-situ phytorestoration technique it is proven to be economical, effi cient and easy to implement under fi eld conditions. Plants grown in metal contaminated sites harbor unique metal tolerant and resistant microbial communities in their rhizosphere. These rhizo-microfl ora secrete plant growth promoting substances, siderophores, phytochelators to alleviate metal toxicity, enhance the bioavailability of metals (phytoremediation) and complexation of metals (phytostabilisation). Selection of right bacteria/consortia and inoculation to seed/ roots of suitable plant species will widen the perspectives of rhizoremediation.

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Rhizosphere microbial populations in contaminated soils

Cited by 131 publications

References 27 publications

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants

Phytoremediation of hydrocarbon contaminants in subantarctic soils: An effective management option

Rhizoremediation of metals: harnessing microbial communities

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