Bacterial Enzymes and Their Role in Decolorization of Azo Dyes - Microbial Degradation of Synthetic Dyes in Wastewaters - page 158

Fig. 12 Proposed
degradation pathway for
Methyl Orange by Lignin
peroxidase

Methyl Orange

ef uent is considered one of the important parameter (Paul et al. 2012 ). Use of plant

bioassays for monitoring toxic effect of azo dyes as well as metabolites on plants
was suggested by many researchers (Paul et al. 2012 ; Kadam et al. 2013a , b ).
Phytotoxicity and microbial toxicity studies revealed that the metabolites formed
after azo dye decolorization were less toxic than original azo dye (Dawkar et al.
2008 ; Dhanve et al. 2008a , b ; Jadhav et al. 2008 ; Kalyani et al. 2008 ; Telke et al.
2008 ). Ames test revealed that the mutagenicity of AV7 even with or without the S9
metabolizing system increased signicantly after static biodegradation and totally
disappeared after aerobic condition (Mansour et al. 2008 ).
Bacteria mediated decolorization of azo dyes under both static anoxic as well as
anaerobic conditions, produces toxic aromatic amines due to enzymatic action of