Bacterial Enzymes and Their Role in Decolorization of Azo Dyes - Microbial Degradation of Synthetic Dyes in Wastewaters - page 156

Methyl Red

Cleavage of azo bond
Purified Azoreductase

+

N, N-dimethylbenzene-
1,4 diamine

2 Amino benzoic acid

Fig. 8 Proposed degradation pathway for Methyl Red by puri ed azoreductase

Congo Red

Cleavage of azo bond
Purified Azoreductase

+

+

3, 4 diaminonapthalene-
1-sulphonic acid

biphenyl 4-4 diamine 3, 4- diaminonapthalene-

1-sulphonic acid

Fig. 9 Proposed degradation pathway for Congo Red by puried azoreductase

The formation of p-hydroperoxy dimethyl amino benzene suggests asymmetric
cleavage of an azo bond in Methyl Red (Telke 2009 ) (Fig. 10 ). The formation of
p-phenyldizine sulfonic acid andp-hydroxy N,N -dimethyl amino benzene indicates

asymmetric cleavage of an azo bond in Methyl Orange (Telke 2009 ) (Fig. 11 ). The
biodegradation of dyes by puri

′

ed laccase con rms their role in decolorization

process.

Methyl Red

Asymmetric Cleavage by
Purified Laccase

p - dimethylamine diazine

2 Hydroxy benzoic acid

Fig. 10 Proposed degradation pathway for Methyl Red by puri ed laccase