83. Ecoethical Technology Using Extracellular Enzymes of Chrysosporium Species
N.S. Kavitha, A. Hilda, S.Gopinath &
K. Latha
Centre for Advanced Studies in Botany,
Guindy Campus, University of Madras, Chennai 600 025.
Five species of Chrysosporium were
investigated for their enzymatic potentiality. Of the five species
of Chrysosporium, C. anam. Arth. cuniculi highlighted itself
to be highly potent for cellulolytic (filter paper and endoglucanase),
and proteolytic activity. Whereas C. pannorum projected
itself to be highly potent for cellulolytic (filter paper) and
lipolytic activity. While C. keratinophilum and C. tropicum
were highly amylolytic fungi. To assess the amylolytic potential
of the fungi 2% w/v of starch used as the substrate. Whereas to
assay the cellulolytic potential, 50 mg of filter paper and 3%
w/v of carboxymethylcellulose (CMC) were used as the substrate.
For assessing the lipolytic and proteolytic activity p-nitrophenyl
palmitate and casein respectively were used as substrates. In
the present investigation, only one species of Chrysosporium
recorded low enzyme activity.
Introduction
Microorganisms produce enzymes which are involved primarily in the degradation of macro-molecules to units capable of being taken into the living cell (Fogarty and Kelly, 1979). Out of the 2000 various enzymes that have been described only a few like amylolytic, cellulolytic, lipolytic and proteolytic enzymes have wide industrial and biotechnological applications.
Amylase is the enzyme which is
capable of degrading starch, glycogen and related polysaccharides
of ‡-1,4 and 1,6 glucosidic linkages. It is used in textile
industry and also in digestive process. Cellulase has been
regarded as enzymes that are capable of degrading linear glucose
polymer of cellulose to give sugar as the end product. It is used
for degrading cellulolytic wastes, such as, agricultural and domestic
wastes, to increase the tensile strain of paper, to produce single
cell protein from cellulosic waste and also in preparation of
alcohol for fuel or chemical production. Lipase are glycerol
ester hydrolase which catalyze the hydrolysis of triacyl glycerol
into fatty acid, partial acyl glycerol and glycerol. It is used
for detergent preparation, lipolyze milk fat, enhancement of dairy
products, pharmaceuticals, synthesis of peptides and is also used
in leather industry. Protease are capable of cleaving protein
into smaller units such as, the peptides and amino acids.
It is used as reagents in laboratory, food industry, dehairing
of skin, feather degradation and also in pharmaceutical industry.
Organisms Chosen For The Present Study
1. Chrysosporium
anamorph of Arthroderma cuniculi;2.
Chrysosporium keratinophilum; 3. Chrysosporium
pannorum;4. Chrysosporium species and 5.
Chrysosporium tropicum. All Chrysosporium species
were isolated from soil samples in school play grounds and public
parks in and around Madras city by hair baiting technique (Ramesh
and Hilda, 1996). The fungal species were grown and maintained
on Sabouraud dextrose agar medium (Dextrose 40g; Peptone 10g;
Agar 25g; Distilled water1000 ml; pH 5.6). Among these five species,
Chrysosporium keratinophilum causes skin diseases.
Amylase
For amylase production, Czapek-dox medium was amended with 2% w/v concentration of starch as sole carbon source. The amylase activity was studied by the estimation of reducing sugars. The absorbance of reducing sugar was measured at 500 nm (Nelson, 1944). One unit of amylolytic activity was the amount of enzyme which liberates 1um of reducing sugar in the assay condition.
Among the five species of Chrysosporium,
the following three species namely Chrysosporium keratinophilum,
Chrysosporium pannorum and Chrysosporium tropicum were
the highly potent fungi for amylolytic activity. However, Chrysosporium
keratinophilum showed maximum activity at 72 hrs. of incubation
(Fig. 1).
Cellulase
For cellulase production, Czapek-dox medium was amended with 3% w/v concentration of carboxy methyl cellulose (CMC) as sole carbon source.
Cellulase activity was monitored by the estimation of reducing sugar using dinitro salicylic method (Miller, 1959), with filter paper (50 mg) or 1% w/v of carboxy methyl cellulose as the substrate. The absorbance of reducing sugar was measured at 575 nm. One unit of filter paper activity was the amount of enzyme which liberates 1 um of reducing sugar in the assay condition. One unit of endoglucanase activity was the amount of enzyme which liberates 1um reducing sugar from 1% CMC in the assay condition.
Among the five species, Chrysosporium
anamorph of Arthroderma cuniculi and Chrysosporium
pannorum appeared to be highly potent fungi for cellulase
activity. However, Chrysosporium ana. Arth. cuniculi and
Chrysosporium pannorum showed maximum filter paper activity
at 120 hrs. of incubation. Whereas, Chrysosporium ana. Arth.
cuniculi showed maximum endoglucanase activity at 168 hrs.
of incubation (Fig. 2a & 2b).
Lipase
For lipase production the fungi were grown
in Yeast- extract - Peptone medium. Exolipase was assayed using
p-nitrophenyl palmitate as the substrate. The lipase activity
was assessed by measuring the increase in absorbance of p-nitrophenol
at 410 nm (Thoner, 1973). One unit of lipase activity was the
amount of enzyme which liberates 1 um of p-nitrophenol
under the assay conditions. Species like Chrysosporium keratinophilum
and Chrysosporium pannorum were the highly potent fungi
for lipolytic activity. However, Chrysosporium pannorum showed
maximum activity at 168 hrs. of incubation (Fig. 3).
Protease
For protease production the fungi were grown in Yeast-extract - Maltose medium. Protease activity was assayed according to the method of Kunitz (1947) using casein as the substrate. The tyrosine liberated by the hydrolysis was quantitatively estimated by measuring the absorbance at 280 nm. One unit of protease activity was the amount of enzyme which liberates 1 ug of tyrosine in the assay conditions. Species of Chrysosporium anamorph of Arthroderma cuniculi showed maximum activity at 168 hrs. of incubation and it was the highly potent fungi for proteolytic activity (Fig. 4).
Among the five species of Chrysosporium,
Chrysosporium anamorph of Arthroderma cuniculi was the highly
potent fungi for filter paper, endoglucanase and protease activity.
While Chrysosporium keratinophilum and Chrysosporium
tropicum were highly potent fungi for amylase activity. Whereas
Chrysosporium pannorum for filter paper and lipase activity.
While only one species of Chrysosporium recorded low enzyme
activity.
Relationship between environmental incidence of fungi and human health
As these fungi were isolated from school
soil environment they have a direct relevance to the health of
the school going children. Many keratinophilic fungi are pathogenic
and are linked with the incidence of dermatomycosis (Ajello,
1953; Mercantini et al., 1980, 1983). All these Chrysosporium
species are keratinophilic fungi which could degrade keratin.
Further, many Ketinophilic fungi are pathogenic and are linked
with the incidence of dermatomycosis, fungal keratitis, Keratitis
of cornea and allergic alveolitis. There are several reports of
Chrysosporium keratinophilum causing diseases in a wide
variety of animals. Their universal occurrence in our human environment
was considered to be of epidemiological significance.
Biotechnological implications
The production of different enzymes by keratinophilic fungi is of immense value for their successful survival and subsequent hydrolysis of keratin. These five species of Chrysosporium have extracellular enzymes which are useful in ecoethical technology such as, for digestive processes (amylase), degradation of cellulolytic waste from pulp and paper industry (cellulase). fermentation and enhancement of dairy products (lipase), for dehairing of skin and feather degradation which remove the contaminants from soil (protease).
Furthermore, these Chrysosporium species
produce large number of enzymes which have biotechnological applications.
Hence if carefully manipulated they can be used for human advantage.
Acknowledgements
The authors thank Prof. A. Mahadevan,
Director, Centre for Advanced Studies in Botany, University of
Madras, Chennai for his encouragement. The financial assistance
by U.G.C and DoEn are greatly acknowledged.
References
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Ph. D thesis, University of Madras, Chennai.
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University of Bochum, Bochum, Germany.
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