Mobilisation of Organic Compounds and Iron by Microorganisms

Harms, Hauke; Wick, Lukas Y.

doi:10.1002/0470094044.ch9

Cited by 6 publications

(2 citation statements)

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“…It is well‐established, that in the subsurface environment, petroleum hydrocarbons accumulate in the solid or nonaqueous liquid phase (NAPL) of soil, which is attributed to the sorption by soil components, dissolution in NAPL, and sequestration in soil micropores. This is because most of the hydrocarbons are scarcely water‐soluble and, therefore, have the tendency to interact with natural organic matter and other soil constituents—processes which render them poorly mobile and restrict their accessibility for microorganisms (Harms & Wick, 2004; Wick et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Biodegradation dynamics disparity between n‐alkanes and polycyclic aromatic hydrocarbons in the vadose zone: A critical review

Galperin¹,

Odencrantz²

2022

Remediation Journal

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In the shallow terrestrial subsurface, bioavailability often controls biodegradation rates of various hydrophobic organic pollutants, such as hydrocarbons. Microorganism‐mediated depletion of n‐alkanes and polycyclic aromatic hydrocarbons (PAHs) in the vadose zone proceeds with distinctively different rates and kinetics. The observed disparity in biodegradation dynamics between these two classes of hydrocarbons are described here in terms of the Best equation, which allows for a complex process of hydrocarbon contaminant depletion to be explained in terms of the physically relevant processes. This equation combines terms describing contributions of two key elements of hydrocarbon biodegradation—the intrinsic catabolic activity of microorganisms and the mass transfer process delivering substrate to active microorganisms. If substrate supply is slow, biodegradation process is availability‐limited because microorganisms consume the substrate faster than it can be delivered. Conversely, when the mass transfer of substrate is faster than the microbial consumption, biodegradation rate tends to be controlled by metabolic kinetics. The evaluation conducted in this study ascertains that the critical factor limiting the rate and extent of PAH biodegradation is the mass transfer rather than the intrinsic microbial activity that appears to govern the rate of n‐alkane biodegradation. The specifics of mass transfer are determined by the magnitude of the substrate–soil interactions. Whereas sorption of n‐alkanes is controlled by weak hydrophobic and van der Waals forces, PAHs tend to bind to the soil matrix by much stronger electron‐donor–acceptor interactions. Stronger interactions between aromatic compounds and soil components translate into the higher activation energies for desorption of PAHs and therefore a slower mass transfer process. This aspect of the substrate–soil interaction explains a more prominent effect of mass transfer limitation on biodegradation dynamics of PAHs compared to that of the corresponding n‐alkanes.

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Section: Introductionmentioning

confidence: 99%

“…The vadose zone water occurs as a thin film on the surface of soil particles and in the smallest interstices between soil particles. The life functions of most microorganisms rely on the water phase and they remain in contact with the aqueous phase (Harms & Wick, 2004). The balance of the pore space is filled with air.…”

Section: Introductionmentioning

confidence: 99%