Myco -Remediation

Contents
Fungi   Facts
 Fungi Functions Remediation  Fungi Links


 

Fungi are non-photosynthesising, heterotrophic organisms that derive their energy from a saprophytic or parasitic existence. They are unicellular, amoeboid,or filamentous, never having the leaves, stems, and roots characteristic of higher plants. Reproduction occurs by sexual or asexual spore formation.

 

Fungi hold an important place in the biosphere

 

 

horse mushroom Orange cup

brain

They don't all look a like

Mycorrhizal Fungi:


Every ounce of soil hosts not just one species, but literally thousands of species of fungi. Of the estimated  6,000,000 species of fungi in the world, we have catalogued only about  50,000. The genetic diversity of fungi is vast by design, and  apparently crucial for life to continue. Fungal cells form long chains called hyphae and may form fruiting bodies such mold or mushrooms (see images above) to disperse spores.



mychoriza 1                     mycoriz


 

Fungi Function:


Under natural conditions plants live in close association with soil organisms called mycorrhizal fungi. These fungi colonize plant roots and extend the root system into the surrounding soil.  Estimates of amounts of mycorrhizal filaments persent in a cubic inch of healthy soil are up to a mile of filaments.  Fungal mats are now known as the largest biological entities on the plant.  The relationship between plants and fungi is beneficial to both;  the plant enjoys improved nutrient and water uptake, disease resistance with superior survival and growth, the fungi receives nutrients in the form of phtosyntates and is able to grow and survive.  It is believed that fungi are responsible for the world of plants being able to inhabit and evolve on land from their aquatic origin.    


The white structures are mycorrhizae.  They link the brown roots and the thin white strands of fungal hyphae radiating out of the soil.

  Depending on the environment in which they are growing, plants may divert up to 80% or more of the net energy fixed as sunlight to below ground processes  Some of this energy goes into root growth; but, a high proportion may be used to feed mycorrhizal fungi and other soil organisms. This is not energy that is lost to the plant. On the contrary, soil organisms living in the root zone greatly influence the ability of plants to establish through effects on nutrient cycling, pathogens, soil aeration, and soil water uptake. Of the various soil organisms that benefit plant establishment, the most is known about mycorrhizal fungi. Roughly 90% of plant species are thought to form mycorrhizae: the combination of fungal and root tissue is called the mycorrhiza and the fungal partner is termed a mycorrhizal fungus.


Saprophytic Fungi:

King Stropharia (saprophyte)

Saprophytic fungi are responsible for breaking down all types of organic matter. They breakdown organic matter by secreting enzymes as well as other exodates which breakdown the hydrocarbon chains that are found in all organic matter. The by products of these reactions are usually more readily available for the uptake and or further break down by other biologic organisms. Many fungi species play an important role in the recycling of complex wood debris and garden wastes. Many of them thrive in varied and complex environments. Some of these saprophytes are capable for breaking down cellulose, lignin, as well as polycyclic aromatic hydrocarbons.

 

 

 

 

Remediation

The mycoremediation process begins with field collection of higher fungi from an area of interest. The process includes the selection, culturing, toxicity screening, preconditioning, mesocosm scale testing, and pilot scale application. The potential use of fungi for the purpose of remediation is just starting to be studied extensively here in the United States.  European and Asian nations are also evaluating the possible uses of fungi and its by products as a tool for remediation. Research is on going; Pacific Northwest National Laboratory (PNNL) Marine Sciences Laboratory (MSL) in Sequim, Washington, Indira Gandi Institute Development and Research in Bombay, India, as well as The Center for Soil and the Environmental Research in Aslow, Norway are but a few facilities who are or have been carrying out research on the remediation potential of fungi. 


Here are but a few uses of fungi for remediation.


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Mycoremediation:

Mycoremediation is being carried out in the United States by Battelle Laboratories in Washington State.

The three types of fungi; saprophytic, parasitic, and mycorrhizal species, vary in use for the type of bioremediation processes.

  • Saprophytic Fungi use enzymes to decompose biologic material
  • Parasitic Fungi are able to destroy bacteria and other pathogens
  • Mycorrhizal Fungi remove substances from the biosphere
The mycelia of fungi like roots of plants, exude enzymes and secondary metabolites that break down molecules which other wise might only be broken down by more toxic substances.  Lignin peroxidases(enzymes), which are exuded by saprophytes dismantle the long chains of hydrocarbons found in the lignin of plant tissue, into simpler forms.  These same enzymes also are able to break apart carbon ring structures found in petrochemicals and other harmful pollutants such as pesticides and PCB's.

Parasitic fungi excrete there own enzymes which have been found to be toxic the bacteria in the soil or substrate where they are growing.  Mycelia of the mycorrhizal fungi attack disease causing pathogens (fungi, bacteria, protozoa, and nematodes) around the roots of plants, which help protect them.  Experiments by Batelle showed that a particular fungus produced an army of crystalline entities, which  advanced in front of the growing mycelium.  The crystals appear to attract motile bacteria by the thousands and to stun them.  The advancing mycelium then digests the bacteria, effectively removing them from the environment.




Mycofiltration:


The potential uses for fungi are vast and only now being explored. Not only can it be used to break down harmful pollutants in the environment but they can also be act as filters for the environment.  Mycofiltration could be used in buffer zones around streams , which would filter the run-off from farms, highways and suburban zones.  The fungi's ability to kill bacteria such as Ecoli have the potential to make it an important ecological tool.





Other Applications: 

  • Fungi have been shown to accumulate radionucliotides, metals, and even rare earth elements.  They would be potentially useful in detecting the presence of and could potentially act as hyper accumulators of these harmful compounds.
  • Fungi are great biodegraders and resultant compost as been proven to enhance plant growth as well as bioremediation activity.  Our land fills, although contained, are only gradually returning their components to a smaller biomas with the same or greater concentrations of toxins.  Why not use fungi to turn these toxic holding areas into usable biomas.
  • Fungi as the ability to enhance plant growth.  The eucalyptus tree is not a native to northern parts of China and attempts at raising this fast growing tree were failing, until fungi was added to the soil.  The mycorrhiza enhanced the plants ability to uptake vital nutrients.  Fungi when used in conjunction with plants used for phytoremediation may also enhance a plants ability to survive and take up pollutants from the soil.
  • The process of paper production involves the removal of lignin from wood pulp.  Current methods employ toxins for the removal of lignin and the bleaching process used to overcome the discoloring effects of the presence of small amounts of lignin in paper.  Fungi have the means, via enzyme production to decompose just the lignin whole leaving the cellulose of wood.  If fungi or its by products were used in paper production we would be able to eliminate a large source of pollution to the environment.

 

Fungi Links

     
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We might be able to save ourselves from ourselves if we work more closely with nature.

Nature does it better.  

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