Mycoremediation of Synthetic Dyes: An Insight into the Mechanism, Process Optimization and Reactor Design - Microbial Degradation of Synthetic Dyes in Wastewaters - page 2

Fig. 1 Simple model of fungal action on naturally-occurring and/or anthropogenically — derived
organic and inorganic substrates (modi ed after Gadd 2007 )

respect to the colonization of insoluble substrates. They have high surface-to-cell ratio
characteristics of laments that maximize both mechanical and enzymatic contact

with the substrate. The extracellular nature of thedegradative enzymes enables fungi
to tolerate higher concentrations of toxic chemicals than what would be possible, if
these compounds had to be brought into the cell. In this case, insoluble compounds,
that cannot cross a cell membrane, are also susceptible to attack.
A lot of research has focused on mycoremediation, which could offer an attractive
decentralized system. However, there has not been much success in translating these
results into actual applications. A critical insight into the mechanism or pathways of
dye transformation as well as process optimization is important while designing the
operational strategy for mycoremediation. Several analytical and statistical tools
have been described in the recent studies to achieve this. Moreover, some studies
focus on the appropriate bioreactor design as per the underlying mechanism of fungal
dye decolorization,while a very few investigations are available on the management
of the dye laden fungal biomass. This chapter describes the recent innovations and
vital advancements in mycoremediation targeting the ease of application.

2 Mechanism of Dye Removal by Fungi

Researchers have been employing various fungi as listed in Table 1 , for dye removal
studies either in living or dead form (Kaushik and Malik 2009 ). Three principal
mechanisms are involved during thedye removal process mediated by fungi;
biosorption, bioaccumulation and biodegradation. Biosorption is a metabolically