Biodegradation of Anthropogenic Organic Compounds in Natural Environments

Niqui‐Arroyo, José‐Luis; Bueno‐Montes, Marisa; Ortega‐Calvo, Josée‐Julio

doi:10.1002/9780470944479.ch19

Cited by 9 publications

(10 citation statements)

References 156 publications

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“…9 Indeed, ettachment to surfaces has been discussed as bioavailability promoting effect due to steeper contaminant concentration gradients and higher mass transfer rates of desorbing contaminants to the cells. 14,17,21 Such enhanced desorption may explain the high observed mineralization extents that were higher than mineralization typically observed in other experimental situations, 24 including the batch assays (∼40%) described in this study. Attached bacteria actively assimilating NAH also produced 14 CO 2 , but remained in the column with biochemically incorporated 14 C, thus resulting in a higher fraction of mineralized NAH in the column effluents.…”

Section: ■ Discussionmentioning

confidence: 47%

“…This enhancement of pollutant biodegradation as a result of an enhanced bioavailability constitutes, therefore, a new end point for the interactions of P. putida G7 cells with AgNPs at low, subtoxic concentrations, to be added to the repellence due to nanoparticle-specific physical effects, independent of the release of silver ions, , and to an enhanced transport through porous materials due to collector saturation . Indeed, ettachment to surfaces has been discussed as bioavailability promoting effect due to steeper contaminant concentration gradients and higher mass transfer rates of desorbing contaminants to the cells. ,, Such enhanced desorption may explain the high observed mineralization extents that were higher than mineralization typically observed in other experimental situations, including the batch assays (∼40%) described in this study. Attached bacteria actively assimilating NAH also produced 14 CO 2 , but remained in the column with biochemically incorporated 14 C, thus resulting in a higher fraction of mineralized NAH in the column effluents.…”

Section: Discussionmentioning

confidence: 99%

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Impact of Chemoeffectors on Bacterial Motility, Transport, and Contaminant Degradation in Sand-Filled Percolation Columns

Jímenez-Sánchez

Wick

Ortega‐Calvo

2018

Environ. Sci. Technol.

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Chemoeffector-mediated bacterial motility and tactic swimming are major drivers for contaminant accessibility and biodegradation at submillimeter scales. In sand-filled percolated columns we tested how and to what degree chemoeffectors influenced bacterial transport and thereby promoted accessibility and degradation of distantly located C-naphthalene (NAH) at the centimeter scale. Sunflower root exudates and silver nanoparticles (AgNPs) were used as chemoeffectors to stimulate opposing effects of motility and tactic swimming of NAH-degrading Pseudomonas putida G7. Sunflower exudates prompted smooth bacterial movement and positive taxis, while AgNPs induced tortuous movement and repellent responses. Compared to chemoeffector-free controls exudates reduced deposition and stimulated bacterial transport during percolation experiments. AgNPs, however, provoked bacterial deposition and concomitant saturation of the collector surfaces (filter blocking) that led to progressively increased percolation of cells. Despite mechanistic differences, both motility patterns supported bacterial transport and promoted mineralization rates of NAH desorbing from a source placed at the column outlet. Observed mineralization rates in the presence of the chemoeffectors were 5-fold higher than those in their absence and similar to NAH-mineralization in well-stirred batch assays. Our results indicate that chemically mediated, small-scale bacterial motility patterns may become relevant for long-distance bacterial transport and the biodegradation of patchy contaminants at higher scales, respectively.

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Section: ■ Discussionmentioning

confidence: 47%

Section: Discussionmentioning

confidence: 99%

Impact of Chemoeffectors on Bacterial Motility, Transport, and Contaminant Degradation in Sand-Filled Percolation Columns

Jímenez-Sánchez

Wick

Ortega‐Calvo

2018

Environ. Sci. Technol.

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“…The analysis showed that the losses of phenanthrene were higher than 95% in all treatments except for the shaken cultures containing only the bacterium. The differences in the extent of mineralization between these treatments (Table ) could be explained by the incorporation of different proportions of substrate carbon into microbial biomass or transformed to partially oxidized byproducts, which is a characteristic of growth-linked biodegradation . Therefore, the distribution of the nonmineralized phenanthrene carbon was determined (Table ).…”

Section: Results and Discussionmentioning

confidence: 52%

“…Taking into account a DOC concentration of 150 mg L –1 in the aqueous phase and the log K oc of phenanthrene, which is 4.16, the predicted total concentration of the compound in the aqueous phase (and the resulting net partitioning rate, assuming instantaneous equilibrium with DOC) , was only enhanced 3-fold, which is significantly lower than the 10-fold enhancement observed (Table ). However, assuming a general figure of 1 pg C per microbial cell, the complete transformation into bacterial cells of the DOC released from the DV8 agar would have caused a 15-fold increase of the bacterial population initially present (10 7 cells mL –1 ). It is possible, therefore, that the DV8 agar contributed to increase the density of suspended bacteria, which eventually attached to the NAPL/water interface, thus promoting its colonization.…”

Section: Results and Discussionmentioning

confidence: 99%

“…No significant loss of 14 CO 2 was expected during the mineralization experiments because all biometer flasks were sealed with Teflon-lined closures. This closed biometer flask system was verified for 14 CO 2 losess in previous work with soils and showed the complete recovery of nonmineralized 14 C residues by combustion of the solids in a biological oxidizer . The mineralization rate of phenanthrene by strain VM552 was calculated using at least five successive points derived from the mineralization curve of the 14 C mineralized versus incubation time.…”

Section: Materials and Methodsmentioning

confidence: 99%

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Mycelium-Enhanced Bacterial Degradation of Organic Pollutants under Bioavailability Restrictions

Sungthong

Tauler

Grifoll

et al. 2017

Environ. Sci. Technol.

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This work examines the role of mycelia in enhancing the degradation by attached bacteria of organic pollutants that have poor bioavailability. Two oomycetes, Pythium oligandrum and Pythium aphanidermatum, were selected as producers of mycelial networks, while Mycobacterium gilvum VM552 served as a model polycyclic aromatic hydrocarbon (PAH) degrading bacterium. The experiments consisted of bacterial cultures exposed to a nondisturbed nonaqueous phase liquid (NAPL) layer containing a heavy fuel spiked with C-labeled phenanthrene that were incubated in the presence or absence of the mycelia of the oomycetes in both shaking and static conditions. At the end of the incubation, the changes in the total alkane and PAH contents in the NAPL residue were quantified. The results revealed that with shaking and the absence of mycelia, the strain VM552 grew by utilizing the bulk of alkanes and PAHs in the fuel; however, biofilm formation was incipient and phenanthrene was mineralized following zero-order kinetics, due to bioavailability limitations. The addition of mycelia favored biofilm formation and dramatically enhanced the mineralization of phenanthrene, up to 30 times greater than the rate without mycelia, possibly by providing a physical support to bacterial colonization and by supplying nutrients at the NAPL/water interface. The results in the static condition were very different because the bacterial strain alone degraded phenanthrene with sigmoidal kinetics but could not degrade alkanes or the bulk of PAHs. We suggest that bacteria/oomycete interactions should be considered not only in the design of new inoculants in bioremediation but also in biodegradation assessments of chemicals present in natural environments.

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