relevance of keratinophilic fungi RESEARCH NEWS Relevance of keratinophilic fungi R K S

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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
                                                                                                           RESEARCH NEWS
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:

CURRENT SCIENCE, VOL. 94, NO. 6, 25 MARCH 2008                                                                                         707

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