Textile Dyes Degradation: A Microbial Approach for Biodegradation of Pollutants - Microbial Degradation of Synthetic Dyes in Wastewaters - page 186

Use of biological methods for detoxi cation of hazardous waste is an emerging

technology with great potential as an effective and inexpensive alternative to earlier
methods for clean-up of polluted environments.
Among microorganisms, fungi possess some unique attributes that, in many
ways, re

ect their morphological and physiological diversity in different habitats.
Fungal biosorption has been studied more extensively because of the availability of
large amount of waste fungal biomass from fermentation industry and the amena-
bility of the microorganisms to genetic and morphological manipulations. Pas-
zczynski et al. ( 1992 ) have examined a new approach to increase the susceptibility
of azo dyes to degradation by aerobic microorganisms, especially by Streptomyces
spp. and Phanerochaete chrysosporium.

3 Fungal Dye Degradation

Dyes industries are one of the major sources of water pollution among different
industrial ef

uents, which are directly poured into the water bodies. In India as well
as in others developing countries, discharges/ef uents from dye industries play a

major role in deteriorating water quality. The wastes from these industries and dye
process are not only responsible for water contamination, but also for many diseases
as well as for the disturbance to the aquatic fauna and ora. The carcinogenic and

persistence nature of azo and many other synthetic dyes, used in textile industry,
have been reported extensively to be mutagenic in nature. Microbes have a great
ability to degrade persistent organic compounds, which are used in dye industries.
With earlier studies on microorganisms, a number of strategies have been applied to
demonstrate or enhance the abilities of organisms to degrade various persistent and
toxic xenobiotics. Fungi and bacteria, both are the principal degraders of organic
matters, but fungi are better known for this purpose. There are about 72,000 species
of fungi and the new species are being added at the rate of about 1,500 each year.
Decolorization of azo dyes by various fungi has been reported by Ra

i et al.
( 1990 ). Fungal biosorption has been studied more extensively because of the
availability of a large amount of waste fungal biomass from fermentation industry
and the amenability of the microorganisms to genetic and morphological manipu-
lations. About 99 % color removal was obtained by adsorption of dye to the cells of

ing et al. ( 1997 ) reported that Bjerkandera adusta and
T. versicolour removed 95 % of HRB 8 dye within four days.
The basidiomycete

lamentous fungi. Hein

s fungus Phanerochaete chrysosporium has unusual degra-
dative capabilities and termed as

'

because of its ability to degrade
lignin, a randomly linked phenyl propane-based polymeric component of wood.
This fungus possesses a great potential and has become a model example for its
commercial and biotechnological use in bioremediation of dyes and lignin-cellu-
losic materials, present in the textile ef

“ white rot fungus ”

uents. Bumpus and Aust ( 1986 ) reported the
capability of this fungus, to degrade a wide variety of structurally diverse organo-
pollutants through its non-speci

cH 2 O 2 -dependent extracellular lignin-degrading