Mycoremediation
Encyclopedia
Mycoremediation, a phrase coined by Paul Stamets
, is a form of bioremediation
, the process of using fungi to degrade or sequester contaminants in the environment
. Stimulating microbial and enzyme
activity, mycelium
reduces toxin
s in-situ. Some fungi are hyperaccumulators, capable of absorbing and concentrating heavy metals
in the mushroom
fruit bodies.
One of the primary roles of fungi in the ecosystem
is decomposition
, which is performed by the mycelium. The mycelium secretes extracellular enzymes and acid
s that break down lignin
and cellulose
, the two main building blocks of plant
fiber. These are organic compounds composed of long chains of carbon
and hydrogen
, structurally similar to many organic pollutants. The key to mycoremediation is determining the right fungal species to target a specific pollutant. Certain strains have been reported to successfully degrade the nerve gases VX
and sarin
.
In an experiment conducted in conjunction with Dr. S. A. Thomas, a major contributor in the bioremediation industry, a plot of soil
contaminated with diesel was inoculated with mycelia of oyster mushroom
s; traditional bioremediation techniques (bacteria) were used on control plots. After four weeks, more than 95% of many of the PAH (polycyclic aromatic hydrocarbon
s) had been reduced to non-toxic components in the mycelial-inoculated plots. It appears that the natural microbial community participates with the fungi to break down contaminants, eventually into carbon dioxide
and water
. Wood-decay fungi
are particularly effective in breaking down aromatic pollutants (toxic components of petroleum
), as well as chlorinated compounds (certain persistent pesticides; Battelle, 2000).
The concept of mycoremediation was explored in the 1984 film Nausicaä of the Valley of the Wind, where vast tracts of fungal forest rehabilitate the planet after catastrophic human polluting and apocalypse.
Mycofiltration
is a similar process, using fungal mycelia to filter toxic waste and microorganism
s from water in soil.
Paul Stamets
Paul E. Stamets is an American mycologist, author, and advocate of bioremediation and medicinal mushrooms.- Research and advocacy :...
, is a form of bioremediation
Bioremediation
Bioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
, the process of using fungi to degrade or sequester contaminants in the environment
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. Stimulating microbial and enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
activity, mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
reduces toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
s in-situ. Some fungi are hyperaccumulators, capable of absorbing and concentrating heavy metals
Heavy metals
A heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
in the mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
fruit bodies.
One of the primary roles of fungi in the ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
is decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
, which is performed by the mycelium. The mycelium secretes extracellular enzymes and acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
s that break down lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
and cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
, the two main building blocks of plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
fiber. These are organic compounds composed of long chains of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, structurally similar to many organic pollutants. The key to mycoremediation is determining the right fungal species to target a specific pollutant. Certain strains have been reported to successfully degrade the nerve gases VX
VX (nerve agent)
VX, IUPAC name O-ethyl S-[2-ethyl] methylphosphonothioate, is an extremely toxic substance whose only application is in chemical warfare as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations in UN Resolution 687...
and sarin
Sarin
Sarin, or GB, is an organophosphorus compound with the formula [2CHO]CH3PF. It is a colorless, odorless liquid, which is used as a chemical weapon. It has been classified as a weapon of mass destruction in UN Resolution 687...
.
In an experiment conducted in conjunction with Dr. S. A. Thomas, a major contributor in the bioremediation industry, a plot of soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
contaminated with diesel was inoculated with mycelia of oyster mushroom
Oyster mushroom
Pleurotus ostreatus, the oyster mushroom, is a common edible mushroom. It was first cultivated in Germany as a subsistence measure during World War I and is now grown commercially around the world for food. However, the first documented cultivation was by Kaufert There is some question about the...
s; traditional bioremediation techniques (bacteria) were used on control plots. After four weeks, more than 95% of many of the PAH (polycyclic aromatic hydrocarbon
Polycyclic aromatic hydrocarbon
Polycyclic aromatic hydrocarbons , also known as poly-aromatic hydrocarbons or polynuclear aromatic hydrocarbons, are potent atmospheric pollutants that consist of fused aromatic rings and do not contain heteroatoms or carry substituents. Naphthalene is the simplest example of a PAH...
s) had been reduced to non-toxic components in the mycelial-inoculated plots. It appears that the natural microbial community participates with the fungi to break down contaminants, eventually into carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
. Wood-decay fungi
Wood-decay fungus
A wood-decay fungus is a variety of fungus that digests moist wood, causing it to rot. Some wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria , are parasitic and colonize living trees. Fungi that not only grow on wood but actually cause it to decay, are called...
are particularly effective in breaking down aromatic pollutants (toxic components of petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
), as well as chlorinated compounds (certain persistent pesticides; Battelle, 2000).
The concept of mycoremediation was explored in the 1984 film Nausicaä of the Valley of the Wind, where vast tracts of fungal forest rehabilitate the planet after catastrophic human polluting and apocalypse.
Mycofiltration
Mycofiltration
Mycofiltration is the process of using mushroom mycelium mats as biological filters. The term was coined by mycologist Paul Stamets.Stamets originally came up with the technique to control E. coli in the water outflow from his property. After planting a mushroom bed in the gulch where the water was...
is a similar process, using fungal mycelia to filter toxic waste and microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s from water in soil.
External links
- The US Patent and Trademark Office Searchable website containing patents and applications related to mycoremediation
- Mycotransformation of organic and inorganic substrates (Gadd 2004)
- Mycoremediation and Its Applications to Oil Spills (Stamets 2010)
- Field Demonstrations of Mycoremediation for Removal of Fecal Coliform Bacteria and Nutrients in the Dungeness Watershed, Washington (Thomas, S. et al 2009)