Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land
Humans are dependent upon soil which supplies food, fuel, chemicals, medicine, sequesters pollutants, purifies and conveys water, and supports the built environment. In short, we need soil, but it has little or no need of us. Agriculture, mining, urbanization and other human activities result in tem...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/2/111 |
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| author | Lerato M. Sekhohola-Dlamini Olajide M. Keshinro Wiya L. Masudi A. Keith Cowan |
| author_facet | Lerato M. Sekhohola-Dlamini Olajide M. Keshinro Wiya L. Masudi A. Keith Cowan |
| author_sort | Lerato M. Sekhohola-Dlamini |
| collection | DOAJ |
| description | Humans are dependent upon soil which supplies food, fuel, chemicals, medicine, sequesters pollutants, purifies and conveys water, and supports the built environment. In short, we need soil, but it has little or no need of us. Agriculture, mining, urbanization and other human activities result in temporary land-use and once complete, used and degraded land should be rehabilitated and restored to minimize loss of soil carbon. It is generally accepted that the most effective strategy is phyto-remediation. Typically, phytoremediation involves re-invigoration of soil fertility, physicochemical properties, and its microbiome to facilitate establishment of appropriate climax cover vegetation. A myco-phytoremediation technology called Fungcoal was developed in South Africa to achieve these outcomes for land disturbed by coal mining. Here we outline the contemporary and expanded rationale that underpins Fungcoal, which relies on in situ bio-conversion of carbonaceous waste coal or discard, in order to explore the probable origin of humic substances (HS) and soil organic matter (SOM). To achieve this, microbial processing of low-grade coal and discard, including bio-liquefaction and bio-conversion, is examined in some detail. The significance, origin, structure, and mode of action of coal-derived humics are recounted to emphasize the dynamic equilibrium, that is, humification and the derivation of soil organic matter (SOM). The contribution of plant exudate, extracellular vesicles (EV), extra polymeric substances (EPS), and other small molecules as components of the dynamic equilibrium that sustains SOM is highlighted. Arbuscular mycorrhizal fungi (AMF), saprophytic ectomycorrhizal fungi (EMF), and plant growth promoting rhizobacteria (PGPR) are considered essential microbial biocatalysts that provide mutualistic support to sustain plant growth following soil reclamation and restoration. Finally, we posit that de novo synthesis of SOM is by specialized microbial consortia (or ‘humifiers’) which use molecular components from the root metabolome; and, that combinations of functional biocatalyst act to re-establish and maintain the soil dynamic. It is concluded that a bio-scaffold is necessary for functional phytoremediation including maintenance of the SOM dynamic and overall biogeochemistry of organic carbon in the global ecosystem |
| first_indexed | 2024-03-09T21:22:26Z |
| format | Article |
| id | doaj.art-1a22c44fd13b453c9d6d10a8ad309ead |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T21:22:26Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-1a22c44fd13b453c9d6d10a8ad309ead2023-11-23T21:17:00ZengMDPI AGMinerals2075-163X2022-01-0112211110.3390/min12020111Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded LandLerato M. Sekhohola-Dlamini0Olajide M. Keshinro1Wiya L. Masudi2A. Keith Cowan3Institute for Environmental Biotechnology, Rhodes University (EBRU), Makhanda 6140, South AfricaInstitute for Environmental Biotechnology, Rhodes University (EBRU), Makhanda 6140, South AfricaInstitute for Environmental Biotechnology, Rhodes University (EBRU), Makhanda 6140, South AfricaInstitute for Environmental Biotechnology, Rhodes University (EBRU), Makhanda 6140, South AfricaHumans are dependent upon soil which supplies food, fuel, chemicals, medicine, sequesters pollutants, purifies and conveys water, and supports the built environment. In short, we need soil, but it has little or no need of us. Agriculture, mining, urbanization and other human activities result in temporary land-use and once complete, used and degraded land should be rehabilitated and restored to minimize loss of soil carbon. It is generally accepted that the most effective strategy is phyto-remediation. Typically, phytoremediation involves re-invigoration of soil fertility, physicochemical properties, and its microbiome to facilitate establishment of appropriate climax cover vegetation. A myco-phytoremediation technology called Fungcoal was developed in South Africa to achieve these outcomes for land disturbed by coal mining. Here we outline the contemporary and expanded rationale that underpins Fungcoal, which relies on in situ bio-conversion of carbonaceous waste coal or discard, in order to explore the probable origin of humic substances (HS) and soil organic matter (SOM). To achieve this, microbial processing of low-grade coal and discard, including bio-liquefaction and bio-conversion, is examined in some detail. The significance, origin, structure, and mode of action of coal-derived humics are recounted to emphasize the dynamic equilibrium, that is, humification and the derivation of soil organic matter (SOM). The contribution of plant exudate, extracellular vesicles (EV), extra polymeric substances (EPS), and other small molecules as components of the dynamic equilibrium that sustains SOM is highlighted. Arbuscular mycorrhizal fungi (AMF), saprophytic ectomycorrhizal fungi (EMF), and plant growth promoting rhizobacteria (PGPR) are considered essential microbial biocatalysts that provide mutualistic support to sustain plant growth following soil reclamation and restoration. Finally, we posit that de novo synthesis of SOM is by specialized microbial consortia (or ‘humifiers’) which use molecular components from the root metabolome; and, that combinations of functional biocatalyst act to re-establish and maintain the soil dynamic. It is concluded that a bio-scaffold is necessary for functional phytoremediation including maintenance of the SOM dynamic and overall biogeochemistry of organic carbon in the global ecosystemhttps://www.mdpi.com/2075-163X/12/2/111coalbioconversionbioremediationhumic substancesopencastphytoremediation |
| spellingShingle | Lerato M. Sekhohola-Dlamini Olajide M. Keshinro Wiya L. Masudi A. Keith Cowan Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land Minerals coal bioconversion bioremediation humic substances opencast phytoremediation |
| title | Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land |
| title_full | Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land |
| title_fullStr | Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land |
| title_full_unstemmed | Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land |
| title_short | Elaboration of a Phytoremediation Strategy for Successful and Sustainable Rehabilitation of Disturbed and Degraded Land |
| title_sort | elaboration of a phytoremediation strategy for successful and sustainable rehabilitation of disturbed and degraded land |
| topic | coal bioconversion bioremediation humic substances opencast phytoremediation |
| url | https://www.mdpi.com/2075-163X/12/2/111 |
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