Use of Fungal Laccases and Peroxidases for Enzymatic Treatment of Wastewater Containing Synthetic Dyes - Green Chemistry for Dyes Removal from Wastewater - page 214

Figure 6.8 Heterocyclic (phenothiazine-structure) dyes and other types of dyes evaluated
for fungal and enzymatic treatment.
Figure 6.9 Examples of carcinogenic degradation byproducts of azo dyes (including diazo
and triazo dyes; left: benzidine, right: 2-nitroaniline).
rotted wood (Figure 6.10). This ability is attributed to secretion of lignin-
oxidizing and degrading enzymes, including laccases, lignin peroxidase
(ligninases, LiP), and manganese-dependent peroxidase (MnP) by these
white rot fungi [26-29]. Lignin is the second most abundant organic poly-
mer composed of aromatic alcohols called monolignols [30,31]. Lignin
exerts yellow to dark brown color owing to its very complex, heteroge-
neous aromatic structure with many crosslinks, as shown in Figure 6.11. It
is also known that lignin is highly resistant to bacterial biodegradation and
becomes part of natural organic matter found in soil and water.
Because of the structural similarity of synthetic dyes and lignin, a major-
ity of the white rot fungi are capable of decolorizing natural and synthetic