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| [[Image:cunninghamella elegans.jpg|thumb|Cunninghamella elegans <http://www.aikis.or.jp>|left|240px]] | [[Image:cunninghamella elegans.jpg|thumb|Cunninghamella elegans <http://www.aikis.or.jp>|left|240px]] | ||
| - | The fungi species [http://en.wikipedia.org/wiki/Cunninghamella_elegans Cunninghamella elegans] is becoming an organism of interest due to its ability to breakdown polycyclic aromatic hydrocarbons. These compounds originate from the combustion of fossil fuels. | + | The fungi species [http://en.wikipedia.org/wiki/Cunninghamella_elegans Cunninghamella elegans] is becoming an organism of interest due to its ability to breakdown polycyclic aromatic hydrocarbons. These compounds originate from the combustion of fossil fuels <ref name="Tortella">Tortella, G.R. & Diez, M.C. (2005). Fungal diversity and use in decomposition of environmental pollutants. Critical Reviews in Microbiology, 31(4), 197-212.</ref>. |
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| <ref>Chen,B.D. Duan, J. Smith S.E. Xiao, X.Y. Zhu, Y.G (2007). Effects of the Arbuscular Mycorrhizal Fungus Glomus mosseae on Growth and Metal Uptake by Four Plant Species in Copper Mine Tailings. Environmental Pollution;(147) 374-380.</ref> | <ref>Chen,B.D. Duan, J. Smith S.E. Xiao, X.Y. Zhu, Y.G (2007). Effects of the Arbuscular Mycorrhizal Fungus Glomus mosseae on Growth and Metal Uptake by Four Plant Species in Copper Mine Tailings. Environmental Pollution;(147) 374-380.</ref> | ||
| <ref>Geyer, R. Kastner, M. Richnow, H. Russow, R. Weib, M (2004). Fate and Metabolism of [N]2,4,6-Trinitrotoluene in Soil. Environmetal Toxicology and Chemistry 23(8) 1852-1860.</ref> | <ref>Geyer, R. Kastner, M. Richnow, H. Russow, R. Weib, M (2004). Fate and Metabolism of [N]2,4,6-Trinitrotoluene in Soil. Environmetal Toxicology and Chemistry 23(8) 1852-1860.</ref> | ||
Revision as of 18:07, 21 March 2013
Contents |
Use of Fungi in Remediation
HEY EVERYONE, THIS IS WHAT I FOUND ONLINE FOR MULTIPLE REFERENCES TO THE SAME FOOTNOTE: FIRST TIME [1] SUBSEQUENT TIMES [1]
Introduction
History
Processes Involved
In situ
The in situ bioremediation method keeps the contaminated material in its place that it exists and performs the treatment. Some examples of in situ bioremediation include bioventing, bioaugmentation, biosparging, biostimulation, and biodegradation. [2] [3] In situ bioremediation techniques are low cost options that are not disruptive to the ecosystem as a whole [3].
However, in situ techniques are limited in that the depth of soil that can be affected by the fungi is restricted, with most methods only reaching depths of up to about 30cm. This limitation is due to the diffusion of oxygen through soils, which is required for many in situ techniques [3].
Ex situ
The ex situ bioremediation method involves the removal of the contaminated material to perform treatment processes. Some examples of ex situ bioremediation include land farming, composting, bioreactors, and biopiles. [2] [3] Ex situ processes are beneficial in that they allow for a greater degree of control over conditions such as pH, aeration, agitation, moistening, and addition of other factors such as electron acceptors, nutrients, solvents or surfactants [4]
Metabolic Processes
Bioremediation includes the degradation of organic substrates, including wood. Plant biomass is a complex network of polysaccharides, proteins, and lignin which can be digested and metabolized by a variety of species of Ascomycota and Basidiomycota fungi [5]. The degradation of lignin by these fungi is considered to be the rate-limiting step in releasing carbon from environments high in lignocellulose compounds. Lignin is a substrate for secondary metabolism, which has to be degraded in order for the fungi to be able to access cellulose as an energy source for primary metabolism. There are three enzymes required to break down are peroxidises, phenoloxidase, and laccase. There are also other enzymes that aid in the digestion of lignin by providing substrates required by the three enzymes named above [6]. These enzymes are involved in demethoxylation, ring hydroxylation and side chain oxidation rather than cleaving the compound as a whole [7].
Species Types Involved
- It has been observed that a wide variety of fungal species have proved effective in remediation treatment; more notably are those of Basidiomycota and Ascomycota. Although these phylum's dominate the majority of the fungi used in remediation, there is evidence that Zygomycota and Glycomycota may also be effective. Within the studies it is reiterated that the reason for the effectiveness of the fungi in remediation lies in the activity of the corresponding enzymes.
Glomus mosseae
Ecological problems have given rise to the exploitation of natural resources, causing pollution and degradation of the environment. In turn, this gives rise to unfavourable conditions for plant growth because of the depleted nutrient acquisition. AM, fungi help increase nutrient supply and build resistance to biotic and abiotic stresses. In areas of pollution, plants are extremely dependent on these fungi to enhance their metabolic activity and diminish the effects of environmental stress.
Belonging to the phylum Glomeromycota, Glomus mosseae is beneficial in encouraging the revegetation of copper (Cu) mine tailings. These tailings are known to damage native vegetation, and contaminate water, land, and air. Metal pollution cause extreme environmental problems for plant growth and development in infected areas. This species is most greatly used as it belongs to arbuscular mycorrhizal fungi, which helps promote plant growth and biomass in metal contaminated soils/substrates. They supply plants with mineral nutrients (especially phosphate and trace elements), improve soil structure (external hyphae and glomalin excreted by external hyphae), and maintain ecosystem stability. Also, they protect host plants against high metal concentrations in soils under metal contamination. Therefore, AM fungi is specifically used to revegetate at mining sites.
The plant species P. vitta and C.Dummundiiinhabit the Cu mine tailings of Tongling southern China, and are extremely dependent on mycorrhizal colonization for growth. These mining sites show a low supply of essential mineral nutrients with excessive metals, and a lower supply of essential plant nutrients. Glomus mussaea help plants obtain more nutrients so resistance to metal contamination can be enhanced. Also, under high metal concentrations in the soil, AM fungi protect host plants against metal toxicity. Therefore,this species of fungi proves to be extremely useful in the rehabilitation of plant growth in mining areas and are a major contribution to the study of bioremediation.
Stropharia rugosoannulata
Some species of basidiomycota, such as Stropharia rugosoannulata, have been shown effective in the breakdown of nitroaromatics, including TNT (2,4,6-trinitrotoluene) by using them as a nitrogen source. Since these compounds are hard to evict from the biosphere where they cause pollution, carcinogenic, and mutanogenic effects, the use of this fungi has been proven useful.
S. rugosoannulata cleaves the nitrogen from the aromatic ring under aerobic conditions, using it as a nutrient source. This allows the decomposition of the compound and a decrease of hazardous potential of residues that pollute the environment.
Phanerochaete chrysosporium
Species of Basidiomycota, Phanerochaete chrysosporium has proven effective in the decolourization of direct dye wastewater, thus making it a successful remediation tool. The reason for this study resided in the fact that many bodies of water are now affected by the amount of dyes used commercially. The ability of basidiomycota to depolarize and mineralize lignin resulted in the degrading synthetic dyes; treatment demonstrated a 90% decolourization within just 7 days of treatment.
Within P. Chrysosporium are multiple extracellular lignin-modifying enzymes that are responsible for degrading a wide variety of compounds. This is due to their low substance specificity; other fungi lack certain structures and show specification making them unable to decolourize certain dyes. Once again, extracellular lignin-modifying enzymes proved prolific when decolourizing direct dye wastewater. There are multiple enzymes involved in the extracellular lignin-modifying process; the most successful enzyme for decolourizing dyes was manganese peroxidises (MnP).
In addition to the efficient enzymes P. Chrysosporium is also superior at decolourizing dyes due to its high pH value and its complex structures. P. Chrysosporium has a pH value of 9 whereas most other fungi possess a pH value in the acidic range, therefore making it more useful in this process. Also the complex –Trisazo, Polyazo and Stilbene structures further assist in the decolourization for direct dye wastewater.
To summarize Phanerochaete chrysosporium is very effective in remediation and possesses great qualities that allow it to be successful in decolourizing direct dye wastewater. These qualities consist of a high pH value, extracellular lignin-modifying enzymes and complex structures; they work as one to denature and eliminate dyes from water bodies around the world. P. Chrysosporium will continue to be used a remediation tool due to its safe and efficient results. [13]
Pleurotus ostreatus
Pleurotus Ostreatus more commonly known as spent white-rot has been used in mycoremediation to eliminate polycyclic aromatic hydrocarbons (PAHs) from oil-based drill cuttings. Sixteen non-substituted PAHs have been identified by the Protection Agency (USPEA) as priority pollutants.
The reason for the high PAH content in drill cuttings is due to the continued use of PAH carrying petroleum fractions which are preferred when working at great depths. Therefore, it is essential that these cuttings are treated before final disposal in order to protect the environment from further damage.
Usually drill cuttings are treated via physico-chemical methods, which are very costly and have environmental implications. Therefore, further research has been conducted to discover a more eco-friendly approach; bioremediation is known to have a relatively low cost and have less impact of the environment. Use of Pleurotus Ostreatus has been discovered to vastly decrease PAH fractions in terms of their properties (molar mass and ring group). For example individual PAH degradation ranged from 97.98% in acenaphthene (3-ring) to 100% in fluorine (3-ring) thus highlighting the extraordinary PAH-removal capacity of spent white-rot fungi.
In conclusion, Pleurotus Ostreatus was discovered to be highly effect in the removal of PAH from oil-based drill cuttings, indicting its effectiveness in remediation. It is also more cost effective than the alternative and has a lower impact on the environment. Spent white-rot fungi utilization in remediation also reduces the amount of the substrate eliminated as waste as well as reducing PAHs in the environment. [14]
Cunninghamella elegans
The fungi species Cunninghamella elegans is becoming an organism of interest due to its ability to breakdown polycyclic aromatic hydrocarbons. These compounds originate from the combustion of fossil fuels [15].
Pleurotus pulmonarius
The Pleurotus Pulmonarius species are a part of the phylum basidiomycota. Pleurotus Pulmonarius is commonly known as oyster mushrooms which are also classified as white rot fungi and has been proven to be a highly effective and important resource for remediation. The oyster mushroom serves many purposes within the remediation process including processes dealing with wastes waters in crop production and landfill pollutants. [16] Pleurotus Pulmonarius is an effective fungus for remediation because it has enzymatic activity that is capable of degrading phenolic related pollutant compounds including chlorinated pesticides like endosulfan and chlorothalonil. Furthermore, it has the capability of degrading cellulose, hemicellulose and ligin. The presence of enzymes including laccase, MnP and phenol oxidase found in Pleurotus Pulmonarius are responsible for the degration of pesticides. More specifically the ligninolytic enzymes are highly efficient degrading environmental pollutants. The ligninolytic enzymes are the most active enzymes in the remediation process within oyster mushrooms because these enzymes are secreted only in the presence of SMS. Pleurotus Pulmonarius was reported to degrade the pesticides more quickly and were able to completely reduce the original concentration of chlorothalonil. In conclusion, Pleurotus Pulmonarius can be efficiently used in remediation methods to help reduce the effects of the pollutants of organochlorine pesticides.
info[27]
Definitions
References
- ↑ 1.0 1.1 1.2 1.3 Perry's Handbook, Sixth Edition, McGraw-Hill Co., 1984
- ↑ 2.0 2.1 Boopathy, R. (2000). Factors limiting bioremediation technologies. Bioresource Technology, 74, 63-67
- ↑ Cite error 8; No text given.
- ↑ Mougin, C., Boukcim, H., Jolivalt, C. (2009). Soil bioremediation strategies based on the use of fungal enzymes. Soil Biology, 17, 123-149./>.
Land farming involves the excavation of the top contaminated layers of soil, sediment and sludge, approximately 10 to 35cm deep, which is mixed in with the soil and is tilled on an occasional basis. The objective of land farming is to assist the aerobic damaging of the contaminants. This method is considered to be cost efficient and low maintenance, and is gaining much interest as an alternative for disposal. <ref></ref> <ref></ref>
Composting is the combination of contaminated material (soil) with organic matter, such as manure and agricultural wastes, which are not harmful and encourage the growth of large populations of fungi, bacteria, viruses and parasites to degrade the contaminated matter. Aerobic conditions and relatively high temperatures are favoured in the method of composting. <ref></ref> <ref></ref>
<ref>Vidali, M. (2001). Bioremediation. An overview. ''Pure and Applied Chemistry'', 73 (7), 1163-1172</li>
<li id="_note-Moore">[[#_ref-Moore_0|↑]] Moore, D., Robson, G.D., Trinci, A.P.J. (2011). 21st Century Guidebook to Fungi. Cambridge, UK: Cambridge University Press</li>
<li id="_note-0">[[#_ref-0|↑]] Pointing, S.b. (2001). Feasibility of bioremediation by white-rot fungi. ''Applied Microbiology and Biotechnology'', 57, 20-33</li>
<li id="_note-Meharg">[[#_ref-Meharg_0|↑]] Meharg, A.A. & Cairney, J.W.G. (2000). Ectomycorrhizas - extending the capabilities of rhizosphere remediation? Soil Biology & Biochemistry, 32(11-12), 1475-1484.</li>
<li id="_note-1">[[#_ref-1|↑]] Vidali, M. (2001). Bioremediation. An overview. ''Pure and Applied Chemistry'', 73 (7), 1163-1172</li>
<li id="_note-2">[[#_ref-2|↑]] Pointing, S.b. (2001). Feasibility of bioremediation by white-rot fungi. ''Applied Microbiology and Biotechnology'', 57, 20-33</li>
<li id="_note-3">[[#_ref-3|↑]] Moore, D., Robson, G.D., Trinci, A.P.J. (2011). 21st Century Guidebook to Fungi. Cambridge, UK: Cambridge University Press</li>
<li id="_note-4">[[#_ref-4|↑]] Boopathy, R. (2000). Factors limiting bioremediation technologies. ''Bioresource Technology'', 74, 63-67</li>
<li id="_note-5">[[#_ref-5|↑]] Balba, M.T., Al-Awadhi, N., Al-Daher, R. (1998). Bioremediation of oil-contaminated soil: microbiological methods for feasibility assessment and field evaluation. ''Journal of Microbiological Methods'', 32, 155-164.</li>
<li id="_note-6">[[#_ref-6|↑]] Faraco, V., Giardina, P., Miele, A., Pezzella, C., & Sannia. (2009). Bio-remidiation of coloured inductrial wastewaters by the white-rot fungi Phanerochaete chrysosporium and Pleurotus ostreatus and their enzymes. Bidegradation, 20(2), 209-220.</li>
<li id="_note-7">[[#_ref-7|↑]] Allagoa, M., Ayotamuno, J., Davis, D., & Okparanma, R. (2011). Mycoremediation of polycyclic aromatic hydrocarbons (PAH) – contaminated oil-based drill-cuttings. African Journal of Biotechnology, 10(26), 5149-5156.</li>
<li id="_note-Tortella">[[#_ref-Tortella_0|↑]] Tortella, G.R. & Diez, M.C. (2005). Fungal diversity and use in decomposition of environmental pollutants. Critical Reviews in Microbiology, 31(4), 197-212.</li>
<li id="_note-Faraco">[[#_ref-Faraco_0|↑]] Faraco, V., Pezzella, C., Miele, A., Giardina, P. & Sannia, G. (2009). Bio-remediation of colored industrial wastewaters by the white-rot fungi Phanerochaete chrysosporium and Pleurotus ostreatus and their enzymes. Biodegradation, 20(2), 209-220.</li>
<li id="_note-8">[[#_ref-8|↑]] Chen,B.D. Duan, J. Smith S.E. Xiao, X.Y. Zhu, Y.G (2007). Effects of the Arbuscular Mycorrhizal Fungus Glomus mosseae on Growth and Metal Uptake by Four Plant Species in Copper Mine Tailings. Environmental Pollution;(147) 374-380.</li>
<li id="_note-9">[[#_ref-9|↑]] Geyer, R. Kastner, M. Richnow, H. Russow, R. Weib, M (2004). Fate and Metabolism of [N]2,4,6-Trinitrotoluene in Soil. Environmetal Toxicology and Chemistry 23(8) 1852-1860.</li>
<li id="_note-10">[[#_ref-10|↑]] Gadd, G.M. (2007). Geomycology: biogeochemical transformations of rocks, minerals, metals and radionuclides by fungi, bioweathering and bioremediation. Mycological Research, 111(1), 3-49.</li>
<li id="_note-11">[[#_ref-11|↑]] Santelli, C.M., Pfister, D.H., Lazarus, D., Sun, Lu, Burgos, W.D. & Hansel, C.M. (2010). Promotion of Mn(II) oxidation and remediation of coal mine grainage in passive treatment systems by diverse fungal and bacterial communities. Applied and Environmental Microbiology, 76(14), 4871–4875.</li>
<li id="_note-12">[[#_ref-12|↑]] Azcon, R. Barea, J.M. Biro, B. Ruiz-Lozano, J.M. Vivas, A. Voros, A (2003). Beneficial Effects of Indigenous Cd-tolerant and Cd-sensitive GLomus mosseae Associated with a Cd-adapted Strain of Brevibacillus sp. in Improving Plant Tolerance to Cd Contamination. Applied Soil Mycology 24(3) 177-186.</li>
<li id="_note-13">[[#_ref-13|↑]] Faraco, V., Pezzella, C., Miele, A., Giardina, P. & Sannia, G. (2009). Bio-remediation of colored industrial wastewaters by the white-rot fungi Phanerochaete chrysosporium and Pleurotus ostreatus and their enzymes. Biodegradation, 20(2), 209-220.</li>
<li id="_note-14">[[#_ref-14|↑]] Adams, P., Lynch, J., & De Leij, F. (2007). Desorption of zinc by extracellularly produced metabolites of Trichoderma harzianum, Trichoderma reesei and Coriolus versicolor. Journal Of Applied Microbiology, 103(6), 2240-2247.</li>
<li id="_note-15">[[#_ref-15|↑]] Carvalho, M. B., Martins, I., Leitão, M. C., Garcia, H., Rodrigues, C., San Romão, V., & Pereira, C. (2009). Screening pentachlorophenol degradation ability by environmental fungal strains belonging to the phyla Ascomycota and Zygomycota. Journal Of Industrial Microbiology & Biotechnology, 36(10), 1249-1256. doi:10.1007/s10295-009-0603-2.</li>
<li id="_note-16">[[#_ref-16|↑]] Juárez, R., Dorry, L., Bello-Mendoza, R., & Sánchez, J. (2011). Use of spent substrate after Pleurotus pulmonarius cultivation for the treatment of chlorothalonil containing wastewater. Journal Of Environmental Management, 92(3), 948-952. doi:10.1016/j.jenvman.2010.10.047.</li>
<li id="_note-17">[[#_ref-17|↑]] Meharg, A.A. & Cairney, J.W.G. (2000). Ectomycorrhizas - extending the capabilities of rhizosphere remediation? Soil Biology & Biochemistry, 32(11-12), 1475-1484.</li>
<li id="_note-Strong">↑ <sup>[[#_ref-Strong_0|27.0]]</sup> <sup>[[#_ref-Strong_1|27.1]]</sup> Strong, P.J. (2008). Fungal remediation and subsequent methanogenic digestion of sixteen winery wastewaters. South African Journal of Enology & Viticulture, 29(2), 85-93.</li></ol></ref>
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