Research Article Open Access
Bioprocessing & Biotechniques
Velu, et al. J Bioproces Biotechniq 2011, 1:4
http://dx.doi.org/10.4172/2155-9821.1000109
Volume 1 • Issue 4 • 1000109
J Bioproces Biotechniq
ISSN:2155-9821 JBPBT, an open access journal
Keywords: Dye degradation; Pleurotus ostreatus;Agricultural wastes;
Laccase; Molecular docking
Introduction
Nearly ten thousand types of synthetic dyes are widely used in the
textile, paper, printing and leather tanning industries, corresponding to
8 x10
5
tonnes per year [1]. he chemical classes of synthetic dyes mostly
used in industrial processes are azo, anthraquinone, sulfur, indigoid,
triphenylmethyl (trityl) and phthalocyanine derivatives, although other
types have many applications such as triazyne[2].Besides the color ef-
fect, the majority of these compounds are toxic, carcinogenic and high-
ly persistent in the environment. Conventional biological treatment of
wastewater is not efective for degradation of dyes, and so a number
of chemical and physical techniques have been used to remove them,
including adsorption to inorganic or organic matrices, decolorization
by photo catalysis and oxidation [3].
However, some ligninolytic microorganisms are capable of degrad-
ing a wide variety of pollutants resembling lignin or its derivative, and
are an attractive option due to low cost, speciicity and the possibility
of total mineralization of these compounds [4]. Basidiomycete’s fungi
are the most eicient lignin-degrading organisms that produce mainly
laccase (EC 1.10.3.2), lignin peroxidase (EC 1.11.10.14) and manganese
peroxidase (EC 1.11.1.13). Laccases are copper-containing oxidases
biocatalyzes the oxidation of electron-rich natural and synthetic or-
ganic substrates, in a non-speciic manner and degrade them into non-
toxic molecular species without forming any recalcitrant metabolites.
So only laccase are been used for bioremediation process due to their
ability to degrade azo, heterocyclic, reactive and polymeric dyes [5].
A number of oxidative enzymes from bacteria, fungi and plants
have been reported to play an important role in numerous waste treat-
ment applications [6], Laccase is one of these oxidative enzymes, which
appears to have a great potential [7] and it alone has a limited efect
on bioremediation due to its speciicity for phenolic subunits in lignin.
Value added bioproducts are at receiving end with greater demand
in the global market. Potentially high titres of enzyme products can
be produced by solid substrate fermentation [8]. Low cost alternative
like agro-wastes are bio-prospected for enhanced enzyme production.
Solid-state fermentation (SSF) is generally deined as a culture for the
production of ligninolytic enzymes because it mimics the natural envi-
ronment of the white rot fungi [9,10]. he inductive capability of rice
bran to laccase production may be related with its phenolic compounds
such as ferulic acid, vanillic acid which were reported to be an inducer
for laccase production by white rot fungi [11,12]. Ferulic acid is found
approximately 0.1% (w/v) and easily prepared in large quantity from
rice bran [13]. Wheat bran provides a conducive, natural habitat for
high secretion of lingo-cellulolytic enzymes without incorporation any
initial amount of carbon and nitrogen supplements, thereby reduc-
ing the process economics. Natural phenolic mediators such as ferulic
acid, coumaric acid and syringic acid are present as abundant source in
wheat bran, which stimulates in enhanced laccase enzyme production
in white rot fungi [14].
Biological processes are eicient at low contaminant concentra-
tions, can be sensitive to shock loads, require long hydraulic retention
times and form large amounts of solid residues [15]. Some of these
disadvantages can be overcome in an enzyme-based reactor, since en-
zymes are able to operate over a broad concentration range [16,17].
he potential advantages of this enzymatic treatment, as compared to
*Corresponding author: Chinnathambi Velu, Research Associate, ARMATS
BIOTEK Research Institute, Kottur, Chennai, India-600085, E-mail: chinna.velu1@
gmail.com
Received July 29, 2011; Accepted November 19, 2011; Published November
21, 2011
Citation: Velu C, Veeramani E, Suntharam S, Kalimuthu K (2011) Insilico Screening
and Comparative Study on the Effectiveness of Textile Dye Decolourization
by Crude Laccase Immobilised Alginate Encapsulated Beads from Pleurotus
Ostreatus. J Bioprocess Biotechniq 1:109 doi: 10.4172/2155-9821.1000109
Copyright: © 2011 Velu C, et al. This is an open-access article distributed under
the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
Abstract
The necessity to safeguard the environment has increased the potential of enzyme usage in textile processing
to ensure eco-friendly production. Laccase enzyme formulation has been used in textile processing such as bio-
bleaching, dyeing, rove scouring, inishing, neps removal, printing, wash-off treatment, dye synthesis and efluent
treatment. However, a high cost associated with biocatalyst production is still a hindrance to their use. Pleurotus
ostreatus is a white-rot fungus that produces a ligninolytic enzyme complex rich in several laccase iso-enzymes. The
main objective of this study is optimize inluence of pH and stability of divalent metal ion-immobilzed crude laccase
enzyme towards decolourization of prototype textile dyes such as Reactive red 80 (Red F3B) and Reactive blue 21(T
Blue G). Wheat bran is used as a lead candidature for production of lignolytic enzyme using Pleurotus osteratus by
solid state fermentation. Two divalent metal ions such as Zn2
+
and Ca2
+
were selected to study the inluence of metal
ions towards the dye decolourization. Results revealed that Ca2
+
ion was better compared to Zn2
+
ion towards enzyme
immobilization and its inluence on dye decolourization in the optimal pH 5.5. Finally, interactions between laccase and
dyes were studied exclusively using Insilco structure based molecular docking methods.
Insilico Screening and Comparative Study on the Effectiveness of Textile
Dye Decolourization by Crude Laccase Immobilised Alginate Encapsulated
Beads from Pleurotus Ostreatus
Chinnathambi Velu
1
*, Ezhilarasan Veeramani
1
, Sridhar Suntharam
2
, Kasinathan Kalimuthu
1
1
Research Associate, ARMATS BIOTEK Research Institute, Kottur, Chennai, India-600085
2
Assistant Professor, Jeppiaar Engineering College, Jeppiaar nagar, Chennai, India-600119