Hericium erinaceus

Hericium erinaceus, commonly known aslion's mane,yamabushitake,bearded tooth fungus, orbearded hedgehog,is a species oftooth fungus. It tends to grow in a single clump with dangling spines longer than1 centimetre (1⁄2inch). It can be mistaken for otherHericiumspecies that grow in the same areas.
Native to North America and Eurasia, the mushrooms are common during late summer and autumn on hardwoods, particularlyAmerican beechandmaple. UsuallyH. erinaceusis consideredsaprophytic, as it mostly feeds on dead trees. It can also be found on living trees, usually in association with a wound. The fruit bodies can be harvested for culinary use and are used intraditional Chinese medicine.
Despite its higher prevalence in Asia,Hericium erinaceuswas first described scientifically in North America.
Both the Latin genus nameHericiumand the species nameerinaceusmean 'hedgehog' inLatin. This is also reflected by theGermanname,Igel-Stachelbart(literally, 'hedgehog-goatee'), and some of its common English names, such asbearded hedgehogandhedgehog mushroom.It is known in Japan asyamabushitake(Kanji:山伏茸,Katakana:ヤマブシタケ) in reference to theyamabushior mountainasceticsof thesyncretisticreligion known asShugendo; while inChinese, it is known ashóutóugū(simplified Chinese:猴头菇;traditional Chinese:猴頭菇;Jyutping:hau4 tou4 gu1) meaning "monkey-head mushroom", and in Europe and the United States aslion's mane.
Thefruit bodiesofH. erinaceusare large, irregular bulbous tubercules. They are5–40 centimetres (2–15+1⁄2inches) in diameter,and are dominated by crowded, hanging, spore-producing spines, which are1–5 cm (1⁄2–2 in) long or longer.
The hyphal system ismonomitic,amyloid, and composed of thin- to thick-walledhyphaethat are approximately 3–15μm(microns) wide. The hyphae also contain clampedseptaandgloeoplerouselements (filled with oily, resinous substances), which can come into thehymeniumas gloeocystidia.
Thebasidiaare 25–40 μm long and 5–7 μm wide, contain foursporeseach and possess a basal clamp. The white amyloid spores measure approximately 5–7 μm in length and 4–5 μm in width. The spore shape is described as subglobose to short ellipsoid and the spore surface is smooth to finely roughened.
It has been observed thatH. erinaceuscan fruit intermittently for 20 years on the same dead tree. It is hypothesized thatH. erinaceuscan survive for 40 years.The mating system ofH. erinaceusspecies found in the U.S. was shown to bebifactorially heterothallic.
Themonokaryoticmycelium growth ofH. erinaceusis slower thandikaryoticgrowth and only a relatively low percentage of monokaryotic cultures yield fruitbodies. Monokaryotic fruitbodies are also smaller than dikaryotic fruitbodies.The monokaryotic mycelium was found to produce fusoid to subglobosechlamydosporesof 6–8 x 8–10 μm size. These spores can stay viable for more than seven years and be stored under anaerobic conditions.Chlamydospore germination requires 30 to 52 hours, with a germination success rate of 32 to 54%.
Spore production is highest at midday, relative to temperature increase and a decrease of relative humidity. Daily trends toward lower relative humidity can favor sporulation, however, levels of relative humidity that are too low do not favor high total spore production.
H. erinaceuscontains diversephytochemicals, includingpolysaccharides, such asβ-glucan, as well ashericenonesanderinacines.From itsessential oil, 77aromaand flavor compounds were identified, includinghexadecanoic acid(26% of total oil composition),linoleic acid(13%),phenylacetaldehyde(9%) andbenzaldehyde(3%), and other oils, such as 2-methyl-3-furanthiol,2-ethylpyrazineand 2,6-diethylpyrazine.Low concentrations ofergosterolare present.
Similar species in the genus includeH. americanumandH. coralloides,both found in eastern North America.Additional species with a resemblance includeDonkia pulcherrima,Radulomyces copelandiiand some withinSarcodontia.
In Europe, the fruit bodies ofH. erinaceusare mainly produced annually from August to November.In North America, they appear from October to February in the west, from July to October in the Mountain states, and from September to February in the east.
In the wild, lion's mane is usually associated with a tree wound and causes awhite pocket rot. Decayed tissue becomes spongy and eventually disintegrates to form a cavity. The distinctive fruiting bodies (basidiocarps) generally appear near the edges of old wounds in autumn.It may be a treeparasite, possibly indicating anendophytichabitat.
H. erinaceushosts in North America include maple, ash, oaks, and eucalyptus.In California, lion's mane has been found oncoast live oak,canyon live oak,interior live oak,California black oak,blue oak, andvalley oak.
Lion's mane is able to withstand cold temperatures and frost conditions.
Brennandania lambi(Acari:Pygmephoroidea) is a mite pest of fungi culture in China. This mite can develop and reproduce on the mycelium ofH. erinaceus. Farm hygiene and heat treatments are the most important pest management strategies that should be followed to counter this acarus.
Hericiumspecies are good competitors against other wood colonisers. They show the ability to maintain their place on dead wood, also when confronted with secondary colonizers, such asTrametes versicolorandStereum hirsutum.Hericium erinaceushas shown to be slightly more competitive than other fungi tooth species, includingCreolophus cirrhatusandH. coralloides.
AlthoughH. erinaceusis native to Europe, it has beenred listedin 13 European countries due to poorgerminationand establishment.
In fungi cultivation, fungalstrainsare analogous to plant varieties in crop breeding.Fungal strains comprise clonal descendants of a single isolation from one fungal colony in a pure culture.The production ofH. erinaceusis widespread in Asia, mostly using extensive production practices on wood logs or stumps.
Although there is considerable scientific research aboutHericiumspp., they are not commonly industrially produced in the West. Accordingly, there are few commercially available strains in the U.S. or Europe and little or no breeding for higher yield or other favorable traits has occurred.Production trials in Egypt report yields ofH. erinaceusaveraging at 165 g per 1 kg medium.
In North America, its production occurs only on a small scale. Most of it is intensive indoor production with only a few small outdoor sites where log cultivation is practiced.
As asaprophytethat occurs on dead wood,H. erinaceusrequires adequatesubstratefactors, including suitable carbon and nitrogen sources, a certain pH value and idealcarbon-to-nitrogen ratio.
Many different substrates have been used to successfully cultivate this mushroom. Depending on the type of cultivation, the substrate can be either solid (artificial log) or liquid (submerged culture and deep submerged culture).
The solid substrate is most commonly a mixture ofsawdustofhardwoodorconifercontaining different complements that may includewheat bran, wheatstraw,soybean meal,corn meal,rice bran, and rice straw. For example,H. erinaceusstrains grow on beech sawdust substrate enriched withwheat bran(20%),ryegrain (25%),soybean meal(7%),rapeseedmeal (10%), or meat-osseousflour (6%).
An example of a liquid substrate composition can beglucosefor the carbon source, soybean powder, corn powder, and wheat bran powder as a complex nitrogen source.The pH values most suitable for the favorable growth ofH. erinaceuswere in the range of 5.0–9.0, with pH 6.0 as optimal.
Hericium erinaceusrequires a humid environment for its growth: 85 to 90% of relative humidity in the air.The incubation temperature most suitable for themycelialgrowth ofH. erinaceuswas found to be 25 °C,and the optimum temperature for vegetative growth was 26 °C.H. erinaceusis unable to grow with awater potentiallower than -5 Mpa.
The artificial cultivation ofH. erinaceuswas first reported in China in 1988. It is cultivated using artificial logs, bottles, and polypropylene bags. However, this type of artificial cultivation is not suitable for industrialized production due to its low yield and long cultivation cycles.
Submerged culture is a type of artificial cultivation ofH. erinaceuswhereby the fungus is grown in a liquid medium. Using this method, a large number of mycelia can be obtained quickly.Bioactive compounds can be sourced from the fruiting bodies, submerged-cultivated mycelial biomass, or liquid-cultivated broth. Growers optimize the culture medium composition to obtain simultaneously high yields ofH. erinaceusmycelial biomass,exopolysaccharides, andpolysaccharides.Submergedfermentationis preferable for the production of mycelial biomass and biologically active metabolites in order to produce a more uniform biomass andextractproducts.
Growth regulators, such as2,4-Dichlorophenoxyacetic acidandgibberellin, were observed to have an advantageous effect on spore germination.Other technologies, such as red and green laser light of low intensity, stimulated spore germination as well as the vegetative growth of mycelium.Argonandheliumlasersalso contributed to the acceleration of fruit body development by 36–51%.
Wild strains ofHericiumspp. can be isolated and cultivated by first gathering fruiting bodies from fallen trees in the natural habitat. The fruiting bodies can then be opened to attain pieces of their inner spore-producing tissue. This tissue is then placed ontoPetri disheswithagarto cultivate fungal colonies at 25 °C. After several transfers to new Petri dishes to verify the purity of the strain, it can be kept at −80 °C for long-term storage.
The edible fruiting bodies are common ingourmetcooking, with young specimens considered the best.Alongsideshiitake(Lentinus edodes) andoyster(Pleurotus ostreatus) mushrooms,H. erinaceusis used as a specialty mushroom in recipes.
H. erinaceusfruiting bodies contain 57%carbohydrates(8% asdietary fiber), 4%fat, and 22%protein.
H. erinaceushas been used intraditional Chinese medicinefor centuries.More recently, it has been included in products such ascoffeeand touted as anadaptogen.