Microbe-Mediated Degradation of Synthetic Dyes in Wastewater - Microbial Degradation of Synthetic Dyes in Wastewaters - page 229

wastewater treatment is the production of degradation products that are more toxic
than the parent material. This challenge can be approached by three principal lines
of attack: the combination of AOPs with biological processes to achieve the
required degree of treatment; the application of molecular biology techniques to
create recombinant strains with higher biodegradation capacities or that produce
more active enzymes to mineralize dyes with less exposure time; and the use of
MFCs to mineralize dyes and produce energy. (b) design novel dyes based on the
introduction of substituents into the chemical structure to enhance their biode-
gradability. The effects of the dye structure on its degradation and the types of
molecules that can be reduced/oxidized more easily are well known. (c) search for
alternatives for dye removal from large volumes of ef uents and get water into the

appropriate condition so that it can be re-used in the same industry. The research in
this area has only been performed at a small scale to date. (d) improve or modify the
production process or implement new processes to reduce water use, eliminate or
minimize the discharge of toxic chemicals, and recycle water as many times as
possible to make companies more eco friendly at a competitive price.

7 Conclusions

The microbial degradation and biosorption of dyes have received much attention, as
these are cost-effective methods for dye removal. The selection of the best treatment
option for the bioremediation of a speci c type of industrial wastewater is a dif cult

task, because of the complex composition of these ef uents. The best option is often

a combination of two or more systems, and the choice of such processes depends on
the ef

uent composition, characteristics of the dye, cost, toxicity of the degradation
products and future use of the treated water. However, the bene ts of the different

processes and the synergistic effect of the combination of such technologies must be
studied carefully to create the best blend, taking advantage of the use of various
strains and consortia isolated from dye-contaminated sites, the isolation of new
microorganisms, such as thermotolerant or thermophilic microorganisms, or the
adaptation of existing ones to consume dyes as their sole carbon and nitrogen
sources in such a way that the ef uents have low values for COD, TOC, color and

toxicity. Through this review, it becomes evident that the development of new
technologies to remove dyes, such as genetic engineering, which involves the
creation of recombinant strains with higher degradation capacities, is important and
should be applied in the future. The development of innovative methodologies,
such as AOPs or MFCs combined with microbiological processes for treating
wastewater containing azo dyes, and the addition of new efforts and approaches in
this direction are mandatory in the future and will play a critical role in increasing
environmental protection.