Relevance of keratinophilic fungi
R. K. S. Kushwaha and Pallavi Gupta
With the invention of the technique of cal habitat. Currently, almost all the Microsporum, Oideondron, Sporendone-
isolation of soil fungi, studies on kerati- habitats of the world have been surveyed ma, Trichophyton and their 17 teleo-
nophilic fungi (Figure 1 a) started in for the presence of keratinophilic fungi1. morphs.
1952 and soil proved to be natural reser- Most of these fungi belong to families Degradation of hair, nails, feathers,
voir of these fungi. Keratinophilic fungi Arthrodermataceae and Onygenaceae, horns and hooves in the soil is carried
also include dermatophytes, which cause order Onygenales in Ascomycetes2. Most out efficiently and these substances are
diseases of the skin and its appendages. of the known fungi grow on higher plants recycled by these fungi. Human hair
Keratinophilic fungi have the unique or their remains, and survive saprophyti- penetration (Figure 1 f ) by mechanical
ability to degrade keratinous substrates, cally. The Arthrodermataceae and Ony- and enzymatic action is a specific feature
e.g. hair (Figure 1 b and c), horns and genaceae are unusual in that majority of of keratinophilic fungi. The keratin-
hooves (Figure 1 d and e), feathers (Fig- them are associated with birds and degrading fungi produce the enzyme
ure 1 g–k), and nails (Figure 1 i). The mammals. These are true fungi that vig- keratinase, which has attracted a great
fungi which degrade these substrates orously degrade keratin and include im- deal of attention in recent times. The
completely are termed as keratinolytic. portant human and animal pathogens. keratinases are involved in enormous in-
Several keratinolytic dermatophytes sur- The most commonly occurring fungi are dustrial and medicinal applications.
vive in the soil, in addition to their clini- Chrysosporium, Geomyces, Malbranhea, Hence, these keratinophilic fungi and their
Figure 1. Keratinophilic fungi and their action. a, Keratinophilic fungal colony; b, c, Keratinophilic fungi on human hair; d, e, Animal
horns and hooves decomposition in soil; f, Human hair breakdown; g, Hen feathers showing growth of these fungi; h, j, Feather de-
composition in soil; i, Bird nails overgrown by these fungi; k–m, Different stages of feather decomposition in vitro; n, Feather powder
as a result of enzymatic decomposition by Gymnoascus intermedius.
706 CURRENT SCIENCE, VOL. 94, NO. 6, 25 MARCH 2008
extracellular metabolites are of practical shirts, etc. These enzymes are also used
relevance. Some of their applications are for cleaning up of drains clogged with 1. Kushwaha, R. K. S., In Biology of Der-
matophytes and other Keratinophilic Fungi
as follows. keratin waste. These keratinases are also
(eds Kushwaha, R. K. S. and Guarro, J.),
Several millions of tonnes of feather employed in the leather industry in hair-
Bilbao, Revista Iberoamericana de Micol.,
waste generated by poultry and other saving dehairing in place of chemical- 2000, pp. 86–92.
livestock leads to troublesome environ- based dehairing. Recently, these kerati- 2. Currah, R. S., Mycotaxon, 1985, 24, 1–
mental pollution. Wastage of protein-rich nases have been found to degrade prion 216.
reserve is ultimately converted into protein leading to the prevention/cure of 3. Shih, J. C. H., Poult. Sci., 1993, 72, 1617–
feather meal using keratinolytic fungi3,4. mad cow disease5,6. Further, keratinases 1620.
The addition of microbial digested are applied in the modification of silk 4. Bertach, A. and Coello, N., Bioresour.
feather meal to the animal feed improves and wool fibres, for acne or psoriasis, for Technol., 2005, 96, 1703–1708.
digestibility and bolstered growth of making vaccines of dermatophytosis and 5. Shih, J. C. H. and Wang, J. J., CAB Rev.:
Perspt. Agric., Vet. Sci. Nutr. Nat. Resour.,
poultry. Nutritional enhancement can also has addictives in skin-lightening agents.
2006, 42, 1–6.
be achieved by hydrolysis of raw feath- In addition to the keratinases, these fungi
6. Wang, J. J., Borwornpinyo, R. and Shih, J.
ers using these keratinolytic fungi (Fig- have the potential to generate natural gas C. H., Enzyme Microb. Technol., 2007, 36,
ure 1 l–n). Microbial-digested feather for fuel from poultry-waste degradation. 758–765.
meal is also used as slow nitrogen- In spite of their high industrial and
releasing fertilizer. Keratinophilic fungi medicinal potential and abundance in the ACKNOWLEDGEMENT. This work was
are used for the production of biodegrad- soil, most of these fungi are neither de- supported by DST and MoEF, New Delhi.
able films, coatings and glue from kerati- posited in Indian Culture Collections nor
nous waste. available with the scientists working on
Keratinases of these fungi are utilized them. Therefore, there is an urgent need R. K. S. Kushwaha* and Pallavi Gupta
in enzyme-based detergents which are to isolate and conserve these fungi for are in the Department of Botany, Christ
used in the removal of keratinous soils, exploitation of their biotechnological po- Church College, Kanpur 208 001, India.
common in the laundry, on collars of tential. *e-mail: email@example.com
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