Prajapati et al.

of various organic nitrogen sources (Saratale et al . 2009;

control and decolorized samples of Reactive Red M5B

Ponraj et al . 2011). In contrast to this, various inorganic

were analysed at 538 nm for assessment of biodegradation.

nitrogen sources like ammonium nitrate and ammonium

The absorption peak for treated dye samples gradually

sulfate have been reported to enhance decolorization of

decreased with the time and disappeared completely,

different dyes by white rot fungi (Asgher et al ., 2009;

which correlate with an apparent decolorization of the

and Singh et al . 2012).

dye. In addition, extra peaks appeared in Uv region may

be due to biotransformation or degradation of the dye and

generation of different metabolites (Fig. 9). Moreover, the

pH of the decolorized medium was around 5.5, indicating

that the color removal was due to biological activity of

the isolate AGYP-1, not because of the change in pH. The

observed results suggested the biodegradation capacity of

the isolate AGYP-1.

3.5.2 HPTLC analysis

The assessment of degraded metabolites was further

performed by HPTLC. Figure 10 demonstrates the

HPTLC analysis of parent dye Reactive Red M5B and

metabolites formed after degradation. The chromatogram

Figure 9: UV-Visible spectral analysis of Reactive Red M5B

when observed under UV light (254 nm), the control

during decolorization by fungal isolate AGYP-1

sample showed presence of 3 bands with R values of 0.45,

f

The decolorization of Reactive Red M5B by isolate

0.62 and 0.76. After decolorization, the control bands

AGYP-1 was monitored in the presence of gelatine

disappeared and new bands with R _f values of 0.31, 0.55

in the range of 0.25 to 10.0 g l -1 (Fig. 8). At 2.5 g l -1

and 0.71 appeared. The results obtained in decolorized

concentration of gelatine, the isolate exhibited maximum

dye sample indicated the formation of new metabolites

decolorization of the dye (98.78±2.5%) within 8 days of

or metabolic intermediates that are different from the

incubation. No significant decolorization of the dye was

parent dye. This signifies the effectiveness of the isolate

obtained with an increase in concentration of gelatine.

AGYP-1 for the degradation of Reactive Red M5B.

The isolate AGYP-1 could grow best (0.308±0.04 g) and

produced high amount of ligninolytic enzymes at 2.5 g

l -1 concentration of gelatine. Under optimized culture

condition, the laccase and MnP activities were 10.28 and

18.66 times higher, which resulted into 1.6 times faster

decolorization of reactive Red M5B by isolate AGYP-1.

The improvement in the production of ligninolytic

enzymes as well as dye removal by different fungal

strains has also been previously reported with optimum

carbon and nitrogen sources (Asgher et al ., 2012).

3.5 Decolorization and degradation analysis of Reactive

Red M5B

Figure 10: Densitometric scan of HPTLC chromatogram of

control Reactive Red M5B (C) and its decolorized samples

3.5.1 UV-visible spectrophotometric analysis

(Ex)

Degradation of dyes can be revealed by examination

of light absorbance spectra during decolorization. The

508