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Cited by 23Metal Extraction and BioleachingBuilding materials and conservationGeochemistry and Elemental Analysis

The DOI matches its Crossref record; 85 of the 85 references it cites were found in a registry or an index; none of the 120 sources its claims cite is checked for support yet.

A Review of Asbestos Bioweathering by Siderophore-Producing Pseudomonas: A Potential Strategy of Bioremediation

Open access
David, Sébastien R., Geoffroy, Valérie A.·2020·Microorganisms
DOI 10.3390/microorganisms8121870PMC PMC7761222
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Abstract

Asbestos, silicate minerals present in soil and used for building constructions for many years, are highly toxic due primarily to the presence of high concentrations of the transition metal iron. Microbial weathering of asbestos occurs through various alteration mechanisms. Siderophores, complex agents specialized in metal chelation, are common mechanisms described in mineral alteration. Solubilized metals from the fiber can serve as micronutrients for telluric microorganisms. The review focuses on the bioweathering of asbestos fibers, found in soil or manufactured by humans with gypsum (asbestos flocking) or cement, by siderophore-producing Pseudomonas. A better understanding of the interactions between asbestos and bacteria will give a perspective of a detoxification process inhibiting asbestos toxicity.

Overview

CoChat Summary

TL;DR

This review synthesizes evidence that siderophore-producing *Pseudomonas*, via pyoverdine (PVD) and pyochelin (PCH), can weather asbestos and asbestos-containing waste (ACW) by removing structural iron, potentially reducing asbestos toxicity. It highlights PVD/PCH mutant and long-term PVD dissolution studies as support for a possible bioremediation strategy.

Key findings

  • Asbestos toxicity is linked to iron (up to 30 wt%) generating reactive oxygen species via the Fenton reaction; chrysotile accounts for 95% of world asbestos production, asbestos cement (AC) represents 80% of world production with ~10% asbestos fibers embedded in 90% cement, and asbestos flocking (AF) contains 90% free asbestos fibers and 10% gypsum.
  • Siderophore-producing *Pseudomonas* produce high-affinity PVDs (Ka = 10^32 M−1; more than 100 different PVDs) and lower-affinity PCH (affinity 10^28.8 M−2); PVD can also complex 16 other lower-affinity metals.
  • Absence of both PVD and PCH greatly reduces iron dissolution from raw asbestos and ACW; in AF, absence of one siderophore is compensated by production of the other, whereas in AC absence of one affects iron removal, with a stronger effect when PCH is absent.
  • Among 10 PVDs tested, PVD-containing supernatants from *P. mandelii* and *P. syringae* were most efficient for iron removal from AF and AC, respectively; long-term PVD renewal cycles decreased iron content in asbestos fibers.

Methods

  • Design: narrative review, not a primary experimental study; it synthesizes literature on asbestos bioweathering by siderophore-producing *Pseudomonas*.
  • Data/sample: published studies on asbestos mineralogy, treatment technologies, siderophore chemistry, and *Pseudomonas*–mineral interactions, including raw asbestos and ACW (AC and AF).
  • Analysis: qualitative synthesis of mechanisms and cited experimental results; no meta-analysis or new data are reported.

Limitations

  • Stated: the specificity of each PVD toward iron and other metals is not yet known; few affinity-constant data exist except for the PVD produced by *P. aeruginosa*; biofilm effects on alteration are controversial and not clearly investigated; further investigation is needed to validate bioremediation.
  • Evident: as a review, it presents no new primary data, and its conclusions rely on cited studies; no quantitative pooled analysis is performed.

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Integrity signals

Registry

Crossref · 10.3390/microorganisms8121870

Cites

85 of 85 references verified0 citation errors · 0 not checkable

Statistics

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Figures

Figure 1 Representation of magnesium and silicon substitution by iron in the chrysotile fiber structure.
Figure 1 Representation of magnesium and silicon substitution by iron in the chrysotile fiber structure.CC BY · PubMed Central
Figure 2 Structures of the pyoverdines from Pseudomonas aeruginosa (A), Pseudomonas mandelii (B) and Pseudomonas syringae (C) and structure of pyochelin from Pseudomonas aeruginosa (D). The pyoverdine ligand groups catecholate, hydroxamate and hydroxy-carboxylate are, respectively, highlighted in red, blue and green. The pyochelin ligand groups phenolate, imine/tertiary amine and carboxylate are respectively highlighted in turquoise, pink and orange. FOHOrn: δN-formyl-δN-hydroxy-ornithine; AcOHOrn: δN-acetyl-δN-hydroxy-ornithine; cOHOrn: cyclo-hydroxy-ornithine; OHAsp: threo-ß-hydroxy-aspartic acid.
Figure 2 Structures of the pyoverdines from Pseudomonas aeruginosa (A), Pseudomonas mandelii (B) and Pseudomonas syringae (C) and structure of pyochelin from Pseudomonas aeruginosa (D). The pyoverdine ligand groups catecholate, hydroxamate and hydroxy-carboxylate are, respectively, highlighted in red, blue and green. The pyochelin ligand groups phenolate, imine/tertiary amine and carboxylate are respectively highlighted in turquoise, pink and orange. FOHOrn: δN-formyl-δN-hydroxy-ornithine; AcOHOrn: δN-acetyl-δN-hydroxy-ornithine; cOHOrn: cyclo-hydroxy-ornithine; OHAsp: threo-ß-hydroxy-aspartic acid.CC BY · PubMed Central
Figure 3 Concentration of iron dissolved from ground raw chrysotile (0.2 g) after 48 h incubation in the presence of succinate medium (control), 200 µM Pseudomonas aeruginosa PAO1 purified pyoverdine (PVD purified) or culture supernatant of the wild type Pseudomonas aeruginosa PAO1 strain producing both siderophores pyoverdine and pyochelin (WT supernatant), a pyoverdine-deficient strain (ΔPVD supernatant), a pyochelin-deficient strain (ΔPCH supernatant), or a pyoverdine- and pyochelin-deficient strain (2Δ supernatant). Error bars indicate the standard errors of the means of three replicates. Bars with the same letter are not significantly different (p > 0.05, Kruskal–Wallis test, three replicates). Adapted from David et al. [78].
Figure 3 Concentration of iron dissolved from ground raw chrysotile (0.2 g) after 48 h incubation in the presence of succinate medium (control), 200 µM Pseudomonas aeruginosa PAO1 purified pyoverdine (PVD purified) or culture supernatant of the wild type Pseudomonas aeruginosa PAO1 strain producing both siderophores pyoverdine and pyochelin (WT supernatant), a pyoverdine-deficient strain (ΔPVD supernatant), a pyochelin-deficient strain (ΔPCH supernatant), or a pyoverdine- and pyochelin-deficient strain (2Δ supernatant). Error bars indicate the standard errors of the means of three replicates. Bars with the same letter are not significantly different (p > 0.05, Kruskal–Wallis test, three replicates). Adapted from David et al. [78].CC BY · PubMed Central
Figure 4 Biosynthetic enzymes for pyoverdine and pyochelin production were tagged with fluorescent protein mCherry to follow the synthesis of proteins involved in siderophore production (PVDJ for pyoverdine and PchA for pyochelin). Bars represent the expression of the pyoverdine and pyochelin biosynthetic pathways after 24 h of Pseudomonas aeruginosa PAO1 growth in casamino acids medium restricted in iron (−Fe) with (+Mg) or without (−Mg) magnesium, in the presence or absence of asbestos flocking (AF) or asbestos cement (AC). P. aeruginosa PAO1 growth in medium −Fe +Mg and −Fe −Mg corresponds, respectively, to the positive and the negative control. Error bars indicate the standard errors of the means of three, five or six replicates. Bars with the same letter are not significantly different (p ≥ 0.05, Kruskal–Wallis test, three, five or six replicates). Adapted from David et al. [79,80].
Figure 4 Biosynthetic enzymes for pyoverdine and pyochelin production were tagged with fluorescent protein mCherry to follow the synthesis of proteins involved in siderophore production (PVDJ for pyoverdine and PchA for pyochelin). Bars represent the expression of the pyoverdine and pyochelin biosynthetic pathways after 24 h of Pseudomonas aeruginosa PAO1 growth in casamino acids medium restricted in iron (−Fe) with (+Mg) or without (−Mg) magnesium, in the presence or absence of asbestos flocking (AF) or asbestos cement (AC). P. aeruginosa PAO1 growth in medium −Fe +Mg and −Fe −Mg corresponds, respectively, to the positive and the negative control. Error bars indicate the standard errors of the means of three, five or six replicates. Bars with the same letter are not significantly different (p ≥ 0.05, Kruskal–Wallis test, three, five or six replicates). Adapted from David et al. [79,80].CC BY · PubMed Central
Figure 5 Concentration of iron dissolved after 18 h incubation from flocking asbestos waste or after 40 h incubation from asbestos cement in the presence of minimal casamino acids medium depleted in iron and magnesium as a control or inoculated with the wild type Pseudomonas aeruginosa PAO1 strain (WT), a pyoverdine-deficient strain (ΔPVD), a pyochelin-deficient strain (ΔPCH), or a pyoverdine- and pyochelin-deficient strain (2Δ). The iron was measured in the bacterial cells (pellet) and supernatants to determine the total amount of total iron extracted. Error bars indicate the standard errors of the means of three replicates. Bars with the same letter are not significantly different (p ≥ 0.05, one-way ANOVA for flocking asbestos waste and Kruskal–Wallis test for asbestos cement, three replicates). Adapted from David et al. [79,80].
Figure 5 Concentration of iron dissolved after 18 h incubation from flocking asbestos waste or after 40 h incubation from asbestos cement in the presence of minimal casamino acids medium depleted in iron and magnesium as a control or inoculated with the wild type Pseudomonas aeruginosa PAO1 strain (WT), a pyoverdine-deficient strain (ΔPVD), a pyochelin-deficient strain (ΔPCH), or a pyoverdine- and pyochelin-deficient strain (2Δ). The iron was measured in the bacterial cells (pellet) and supernatants to determine the total amount of total iron extracted. Error bars indicate the standard errors of the means of three replicates. Bars with the same letter are not significantly different (p ≥ 0.05, one-way ANOVA for flocking asbestos waste and Kruskal–Wallis test for asbestos cement, three replicates). Adapted from David et al. [79,80].CC BY · PubMed Central
Figure 6 Concentration of iron dissolved from asbestos flocking or asbestos-cement in the presence of 100 μM of various pyoverdine-containing supernatants (SN) after 24 h of contact. Error bars indicate the standard errors of the means of three or five replicates. Bars with the same letter are not significantly different (p ≥ 0.05, Kruskal–Wallis test, three or five replicates). Adapted from David et al. [72,80].
Figure 6 Concentration of iron dissolved from asbestos flocking or asbestos-cement in the presence of 100 μM of various pyoverdine-containing supernatants (SN) after 24 h of contact. Error bars indicate the standard errors of the means of three or five replicates. Bars with the same letter are not significantly different (p ≥ 0.05, Kruskal–Wallis test, three or five replicates). Adapted from David et al. [72,80].CC BY · PubMed Central
Figure 7 Iron removal from asbestos flocking or asbestos cement after 24 h renewal cycles (C1 to C9) in the presence of 100 μM of Pseudomonas mandelii, Pseudomonas aeruginosa or Pseudomonas syringae pyoverdine-containing supernatants (SN). Adapted from David et al. [72,80].
Figure 7 Iron removal from asbestos flocking or asbestos cement after 24 h renewal cycles (C1 to C9) in the presence of 100 μM of Pseudomonas mandelii, Pseudomonas aeruginosa or Pseudomonas syringae pyoverdine-containing supernatants (SN). Adapted from David et al. [72,80].CC BY · PubMed Central
Figure 8 STEM images of chrysotile fibers from asbestos flocking and asbestos cement after respectively 42 and 20 days of total incubation in the presence of succinate (A) or casamino acids (B) medium as a control, Pseudomonas mandelii (C) or Pseudomonas syringae (D) pyoverdine-containing supernatants (SN). Atomic ratios of Fe/Si of total area (E). Adapted from David et al. [72,80].
Figure 8 STEM images of chrysotile fibers from asbestos flocking and asbestos cement after respectively 42 and 20 days of total incubation in the presence of succinate (A) or casamino acids (B) medium as a control, Pseudomonas mandelii (C) or Pseudomonas syringae (D) pyoverdine-containing supernatants (SN). Atomic ratios of Fe/Si of total area (E). Adapted from David et al. [72,80].CC BY · PubMed Central

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Citations

Cites

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Research works printed but not linked: 3

  1. 2012, Impact of the microbial siderophores and phytosiderophores on the iron assimilation by plants: A synthesis, Rev. Fitotec. Mex., 35, 9
  2. Prasad, R., Gill, S.S., and Tuteja, N. (2018). Chapter 10-Pseudomonas fluorescens: A plant-growth-promoting rhizobacterium (PGPR) with potential role in biocontrol of pests of crops. Crop Improvement through Microbial Biotechnology, Elsevier.
  3. Cocozza, 1997, Siderophore production and associated characteristics in rhizosphere and non-rhizosphere fluorescent pseudomonads, Annali. Microbiol. Enzimol., 47, 17

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Metadata

Authors
David, S. R., & Geoffroy, V. A.
Affiliations
  • SOMEZ, Parc Marcel Dassault, 34430 Saint Jean de Vedas, France
  • Centre National de la Recherche Scientifique (FR)
Corresponding author
Geoffroy, Valérie A.
Venue
Microorganisms
Publisher
MDPI AG
Published
2020-11-26
Volume
8
Issue
12
Pages
1870
ISSN
2076-2607 (ISSN-L)
DOI
10.3390/microorganisms8121870
PMC
PMC7761222
OpenAlex
W3107860740
Semantic Scholar
b2b2391c2e215ccf912ab9caf13dad7baed9d7af
Cited by
23
References
85
Citations by year
2026: 2 · 2025: 5 · 2024: 6 · 2023: 5 · 2022: 2 · 2021: 3
FWCI
0.17
Type
journal article
Language
en
Open access
Licence
Locations
  • Microorganisms (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by)
  • HAL (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
  • french R & D plan for asbestos removal (PRDA-SU06-17-006)
  • French environment and energy management agency (TEZ16-13)
  • SOMEZ (TEZ16-13)
Topics
  • Physical Sciences › Materials Science › Metals and Alloys › Metal Extraction and Bioleaching
  • Physical Sciences › Earth and Planetary Sciences › Earth-Surface Processes › Building materials and conservation
  • Physical Sciences › Earth and Planetary Sciences › Geochemistry and Petrology › Geochemistry and Elemental Analysis
Keywords
siderophores, Pseudomonas, asbestos toxicity, iron chelation, mineral alteration, asbestos cement

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David, S. R., & Geoffroy, V. A. (2020). A Review of Asbestos Bioweathering by Siderophore-Producing Pseudomonas: A Potential Strategy of Bioremediation. Microorganisms. https://doi.org/10.3390/microorganisms8121870

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