Impact of low-molecular-weight organic acids on the availability of phenanthrene and pyrene in soil

Ling, Wanting; Ren, Lili; Gao, Yanzheng; Zhu, Xuezhu; Sun, Bо

doi:10.1016/j.soilbio.2009.08.003

Cited by 104 publications

(72 citation statements)

References 42 publications

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“…In contrast, over the past ten years many studies have demonstrated the beneficial impacts of biostimulation (amendment) with root exudates on hydrocarbon degradation [7,69,230,231,255,258,259,[263][264][265]298,299]. Furthermore, root exudates stimulate lateral gene transfer in the rhizosphere [283,289], including hydrocarbon degrading genes [228].…”

Section: Discussionmentioning

confidence: 99%

“…Yang et al [69] and Ling et al [7,265] found that LMWOAs (such as citric and oxalic acids) significantly enhanced the desorption availability of hydrocarbons from a contaminated soil, and continued to desorb more PAHs from soil during multiple desorption cycles. In fact, the mechanism by which LMWOAs promote desorption of PAHs from soil was proposed to begin by a disruption of soil Secondly, plants may directly improve degradation via the root exudation of enzymes, such as laccases, phenol oxidases and peroxidases which catalyze the oxidation of various hydrocarbons and degrade them into intermediate products ( Figure 3B) [54,67].…”

Section: Impact Of Root Exudates On Hydrocarbon Degradationmentioning

confidence: 99%

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Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

2016

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Rhizoremediation is a bioremediation technique whereby microbial degradation of organic contaminants occurs in the rhizosphere. It is considered to be an effective and affordable "green technology" for remediating soils contaminated with petroleum hydrocarbons. Root exudation of a wide variety of compounds (organic, amino and fatty acids, carbohydrates, vitamins, nucleotides, phenolic compounds, polysaccharides and proteins) provide better nutrient uptake for the rhizosphere microbiome. It is thought to be one of the predominant drivers of microbial communities in the rhizosphere and is therefore a potential key factor behind enhanced hydrocarbon biodegradation. Many of the genes responsible for bacterial adaptation in contaminated soil and the plant rhizosphere are carried by conjugative plasmids and transferred among bacteria. Because root exudates can stimulate gene transfer, conjugation in the rhizosphere is higher than in bulk soil. A better understanding of these phenomena could thus inform the development of techniques to manipulate the rhizosphere microbiome in ways that improve hydrocarbon bioremediation.

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Section: Discussionmentioning

confidence: 99%

Section: Impact Of Root Exudates On Hydrocarbon Degradationmentioning

confidence: 99%

Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

2016

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“…Citrate, malate and oxalate have been shown to increase the desorption of phenanthrene and pyrene from various soils; however, relatively high (up to 1000 mM compared to up to 600 µM in rhizosphere) concentrations were used (Ling et al, 2009;An et al, 2010An et al, , 2011Gao et al, 2010). The concentration of carboxylates applied in this study was chosen to be representative of the rhizosphere (e.g., 600 µM) and may have been too low to have caused any significant desorption effects on the PHCs.…”

Section: Citrate and Malonate Did Not Significantly Enhance The Degramentioning

confidence: 99%

“…In addition, carboxylates have the capacity to enhance soil phosphorus supply and, hence, microbial growth and activity through phosphate desorption either due to anion exchange or their ability to chelate to metal cations (e.g., Al 3+ , Fe 3+ and Ca 2+ ) (Jones and Darrah, 1994;Ryan et al, 2001;Shane and Lambers, 2005). Carboxylates may also function to increase the bioavailability of PHCs by promoting their desorption from the soil matrix (Ling et al, 2009;An et al, 2010An et al, , 2011Gao et al, 2010;Keiluweit et al, 2015), although this would depend on soil type and may require higher carboxylate concentrations than reportedly occur in soils (Ryan et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Citrate and malonate increase microbial activity and alter microbial community composition in uncontaminated and diesel-contaminated soil microcosms

Martin

George

Price

et al. 2016

SOIL

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Abstract. Petroleum hydrocarbons (PHCs) are among the most prevalent sources of environmental contamination. It has been hypothesized that plant root exudation of low molecular weight organic acid anions (carboxylates) may aid degradation of PHCs by stimulating heterotrophic microbial activity. To test their potential implication for bioremediation, we applied two commonly exuded carboxylates (citrate and malonate) to uncontaminated and diesel-contaminated microcosms (10 000 mg kg −1 ; aged 40 days) and determined their impact on the microbial community and PHC degradation. Every 48 h for 18 days, soil received 5 µmol g −1 of (i) citrate, (ii) malonate, (iii) citrate + malonate or (iv) water. Microbial activity was measured daily as the flux of CO 2 . After 18 days, changes in the microbial community were assessed by a community-level physiological profile (CLPP) and 16S rRNA bacterial community profiles determined by denaturing gradient gel electrophoresis (DGGE). Saturated PHCs remaining in the soil were assessed by gas chromatography-mass spectrometry (GC-MS). Cumulative soil respiration increased 4-to 6-fold with the addition of carboxylates, while diesel contamination resulted in a small, but similar, increase across all carboxylate treatments. The addition of carboxylates resulted in distinct changes to the microbial community in both contaminated and uncontaminated soils but only a small increase in the biodegradation of saturated PHCs as measured by the n-C17 : pristane biomarker. We conclude that while the addition of citrate and malonate had little direct effect on the biodegradation of saturated hydrocarbons present in diesel, their effect on the microbial community leads us to suggest further studies using a variety of soils and organic acids, and linked to in situ studies of plants, to investigate the role of carboxylates in microbial community dynamics.

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“…As a pollutant, they are of concern because some of their compounds have been identified as carcinogenic, mutagenic, and teratogenic [2]. Incomplete combustion, pyrolysis of organic materials by industry, agriculture and traffic, diagenetic alteration of natural organic matter, long-term wastewater irrigation, reused sewage sludge and fertilizer use in agricultural production result in high concentrations of Polycyclic aromatic hydrocarbons (PAHs) in farmland soil [3,4,5] [6] for consumption pattern in Nigeria, in the SouthSouth region where Rivers state is situated tuber and plantain consumption is 35.09%. Together, they represent approximately onethird of the total foods consumed in the region.…”

Section: Introductionmentioning

confidence: 99%

Distribution of polycyclic aromatic hydrocarbons in some selected tubers grown in farmlands in Alakahia and Eleme communities, Rivers, Nigeria

Joy

Okonkwo

2017

Int. J. Sci. World

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The present study investigated the level of polycyclic aromatic hydrocarbon (PAH) in three commonly consumed tubers grown in farmlands in two communities-Alakahia and Eleme, Rivers state, Nigeria. The total PAH concentrations in the tubers ranged from 2.94 ± 0.26 to 70.83 ± 1.56 -µg/kg. Pyrene was the predominant PAH in most of the tuber samples from Alakahia and Eleme communities. The PAH profile in the tuber samples were dissimilar at both communities when compared. The Low molecular weight PAH to High molecular weight PAH ratio (LMW-PAH/HMW-PAH) showed that the high molecular PAH were predominant in the tubers thus suggesting that the source of PAH in the tubers are of pyrogenic origin.

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Impact of low-molecular-weight organic acids on the availability of phenanthrene and pyrene in soil

Cited by 104 publications

References 42 publications

Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

Citrate and malonate increase microbial activity and alter microbial community composition in uncontaminated and diesel-contaminated soil microcosms

Distribution of polycyclic aromatic hydrocarbons in some selected tubers grown in farmlands in Alakahia and Eleme communities, Rivers, Nigeria

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