• Mycoremediation is the use

of fungi to degrade

pollutants from the

environment.

• Fungi have the innate

capability to breakdown

molecules, disassembling

long-chained toxins into

simpler less toxic chemicals.

• Fungi can remove heavy

metals by channeling them

into their fruitbodies.

• Mycoremediation practices

involve mixing mycelium into

contaminated soil, or placing

mycelial mats over toxic sites.

• Enzymes are secreted by

certain fungi that digest lignin

and cellulose, the primary

building blocks of wood. These

same enzymes can break down

a wide range of toxins that

have similar bonds found in

wood.

• Fungi can be broken down into

2 subgroups that pertain to

bioremediation: brown rotters

and white rotters

• What is the difference between white-rot fungi and brown-rot

fungi?

• White rot fungi are excellent

mycoremediators of toxins held

together by hydrogen-carbon

bonds. Enzymes secreted by white

rotters include lignin peroxidases,

manganese peroxidases, and

laccases.

• Extra-cellular lignin modifying

enzymes have very low substrate

specificity so they are able to

mineralize a wide range of highly

recalcitrant organopollutants that

are similar in structure to lignin.

• The enzymes of the lignin

degradation system of white-rot

fungi are extracellular, thus

negating the need to internalize

the pollutants and enabling the

fungi to tolerate a high

concentration of pollutants.

• White rot-fungi cannot utilize lignin

as a source of energy for growth

and instead require cosubstrates as

a carbon source.

• White rot fungi grow by hyphal

extension and thus can reach

pollutants in the soil in ways that

other organisms cannot.

• Mycelium contribute to biodiversity in nature by providing a nutrient source

for microbes aiding in the decomposing process when there is an imbalance

in the environment caused by the presence of a pollutant.

• Mycoremediated areas also provide the framework to jumpstart the

ecological restoration process.

• When selecting mushrooms for remediating a toxic site choose species that

naturally grow there first.

• Spent mushroom compost is much more biodiverse and thus more effective

than a pure culture in remediating a polluted site.

• Why is spent mushroom mycelium much more effective in

bioremediation process than a pure culture of mycelium?

• Washington State Department of Transportation in Bellingham, WA was

granted a permit to implement mycoremediation of its maintenance yard.

• 4 piles of contaminated soil were set aside on 4 sheets of 6mm black

polyethylene tarps.

• Into one pile 3 cubic yards of pure culture sawdust spawn was mixed into soil

• The spawn was sandwiched in layers within the soil.

• The other piles received no mycelia. 2 were given bacterial treatments and 1

was an untreated control.

• Approximately 4 weeks later all 3 of the piles were black and

lifeless with odor of diesel and oil while the myceliated pile

flourished with oyster mushrooms.

• Drill cuttings are mixtures of rocks and particulates released

from geologic formations in the drill holes made for crude oil

drilling.

• Spent white-rot fungi (pleurotus ostreatus) substrate was used to

treat drill cuttings in Nigeria under laboratory conditions.

• Four options of different treatment levels were tested in 10L

plastic reactors containing fixed masses of the drill cuttings

(2000g) and fresh top soil (500g) inoculated with varying

masses of the fungal substrate.

• Fungi are a versatile biosorption group as they can grow under

extreme conditions of pH, temperature and nutrient availability

as well as high metal concentration

• Biosorption is a term which involves the use of microbes to

detoxify and control environmental contaminants.

• Fungi biomasses have a high percentage of cell wall material

that show excellent metal-binding properties.

• Fungal cell wall has the key role in heavy metals sorption. The

isolated cell wall fraction accounts for 38–77% of metal uptake

and its sorption capacity was 20–50% higher than the overall

binding capacity of the mycelium.

• The heavy metal binding capacity is dependent on the mycelial

age and on the composition of culture media used for

cultivation. These phenomena are probably due to the changes

in cell wall composition.

• Inability of the fungus to compete with native microbes in soils.

Bacteria could either inhibit the growth of fungi or in

combination with fungi, enhance degradation of pollutant.

• Understanding of nutrient requirements of the fungus enabling it

to thrive at a contaminated site.

• Molecular biology including the major genes encoding lignin

peroxidases and manganese-dependent peroxidases.

• More large scale field studies to verify results of bench-scale

tests.

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