full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and Pharmacy
Vol. 5 (3) 1273 -1281 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online)
1277
the increasing concentration of H 2
O 2
and
maximum decolorization was observed at a
concentration of 1.0 mM H 2
O 2
that remained
substantially unaffected till 1.2 mM H 2
O 2
. At
concentrations of hydrogen peroxide beyond 1.2
mM there was decrease in decolorization of both
RB15 and RR4, although on comparison RR4
showed more reduction in decolorization than
RB15.
Effect of temperature and pH on the extent of
reactive dye decolorization : The results of
temperature activity plot are shown in Fig.4. Both
dyes (RB15 and RR4) showed sufficient
decolorization in temperature range of 40°C to
50°C. Buffers (pH 2.0 to pH 10.0) were used to
find out the range of pH in which significant
decolorization was observed. The results of pH
activity plot are shown in Fig.5. An acidic range
of pH (4.0 to 5.0) was better suited for dye
decolorization. A pH optimum recorded for both
the dyes was pH 5.0. The extent of decolorization
significantly decreased in alkaline medium.
Effect of time on the extent of reactive dye
decolorization : The extent of decolorization of
both dyes RB15 and RR4 as a function of time
is shown in Fig.6. RB15 showed maximum
decolorization in 90min whereas RR4
decolorized maximally after 3h of incubation at
40°C. However, no effective increase was
observed when the dyes were further incubated
for longer durations. Sufficient amount of RB15
was decolorized within 60 min while the
Reactive Blue 15 Reactive Red 4
Fig.4:Temperature activity plot. Reactive dye
decolorization as a function of temperature (20°C to 90°C).
Reactive Blue 15 Reactive Red 4
Fig.6: Time activity plot. Reactive dye decolorization as
a function of time (30 min to 300 min).
decolorization of RR4 was slow in the same time
interval.
Reactive Blue 15 Reactive Red 4
Fig.5: pH activity plot. Reactive dye decolorization as a
function of pH (pH 2.0 to pH 10.0). The buffers were
glycine-HCl (pH 2.0, 3.0 and 4.0), sodium acetate (pH 5.0),
sodium phosphate (pH 6.0, 7.0 and 8.0), and Tris-HCl (pH
9.0 and 10.0).
Discussion
The reactive dye decolorization ability of
peroxidase isolated from Trichosanthes dioica
has been evaluated in the presence of redox
mediators under different sets of conditions. The
enzyme pointed gourd peroxidase (PGP) has
been partially purified and used for studying
decolorization of reactive dyes using simple
techniques. The emphasis on enzyme purification
Simple approach to reactive dye decolorization