full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
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Current Trends in <strong>Biotechnology</strong> <strong>and</strong> <strong>Pharmacy</strong><br />
Vol. 5 (3) 1273 -1281 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online)<br />
1276<br />
Results<br />
Effect <strong>of</strong> different redox mediators on the extent<br />
<strong>of</strong> reactive dye decolorization : The effect <strong>of</strong><br />
different redox mediators on dye decolorization<br />
by PGP is shown in Fig. Ia. Among the six<br />
different redox mediators studied for dye<br />
decolorization, HOBT was most effective in<br />
decolorizing the dyes. The extent <strong>of</strong><br />
decolorization was 98.6% <strong>and</strong> 68.2% for RB15<br />
<strong>and</strong> RR4 respectively in the presence <strong>of</strong> HOBT.<br />
The other redox mediators were relatively less<br />
effective. Fig.1b shows the effect <strong>of</strong> increasing<br />
concentrations <strong>of</strong> HOBT (0.05 to 2.0 mM) on<br />
RB15 <strong>and</strong> RR4. With increasing concentration<br />
<strong>of</strong> HOBT there was an increase in the extent <strong>of</strong><br />
decolorization <strong>of</strong> both dyes. Maximum<br />
decolorization was achieved in the presence <strong>of</strong><br />
1.0 mM HOBT. At concentration above 1.0mM<br />
there was insignificant change in percent<br />
decolorization <strong>of</strong> the dyes.<br />
Effect <strong>of</strong> enzyme concentration <strong>and</strong> pH on the<br />
extent <strong>of</strong> reactive dye decolorization : Fig.2<br />
shows the extent <strong>of</strong> decolorization <strong>of</strong> RB15 <strong>and</strong><br />
RR4 with varying concentrations <strong>of</strong> PGP. The<br />
maximal decolorization for these two dyes was<br />
observed at PGP concentration <strong>of</strong> 0.45EUmL -1 .<br />
At concentrations above this, there was no<br />
remarkable change in dye decolorization. Fig.3<br />
shows the percent decolorization improved with<br />
Reactive Blue 15 Reactive Red 4<br />
HOBT Conc. (mM)<br />
Fig.1a. Reactive dye decolorization as a function <strong>of</strong><br />
different redox mediators. The concentration <strong>of</strong> each redox<br />
mediator viz., syringaldehyde, guaiacol, 1-<br />
hydroxybenzotriazole (HOBT), vanillin, bromophenol, <strong>and</strong><br />
quinol was 0.5mM; other conditions were 0.8mM H 2<br />
O 2<br />
,<br />
100mM glycine HCl buffer, pH 4.0 for 60 min at 37°C.<br />
(λ max<br />
for RB 15 <strong>and</strong> RR 4 are 675nm & 517nm<br />
respectively).<br />
Fig.1b. Reactive dye decolorization as a function <strong>of</strong><br />
different concentrations <strong>of</strong> HOBT (0.05 to 2.0 mM).<br />
% Dye decolorization % Dye decolorization<br />
Enzyme in Eu/ml<br />
Reactive Blue 15 Reactive Red 4<br />
Fig. 2. Enzyme activity plot. Reactive dye decolorization<br />
as a function <strong>of</strong> different enzyme (PGP) concentrations<br />
(0.065 to 0.50 EUmL -1 ).<br />
H 2<br />
O 2<br />
Conc. in mM<br />
Reactive Blue 15 Reactive Red 4<br />
Fig. 3. Hydrogen peroxide activity plot. Reactive dye<br />
decolorization at different concentrations <strong>of</strong> H 2<br />
O 2<br />
(0.2 to<br />
1.8 mM).<br />
Farrukh Jamal