anaerobic degradation. Anaerobic degradation is accomplished by the anaerobic
bacteria (Seshadri et al. 1994). In this case, acidic medium-acting bacteria act on
organic substances, such as carbohydrates and fats. Such organic materials can be
converted into alcohols and other basic compounds through the catalysis of acidic
bacteria. These outcome products stimulate the acetogenic bacteria, which then
transform them into carbon dioxide and molecular hydrogen. Anaerobic reduction
of azo dyes can be an effective and economic treatment process for color removal
from textile wastewaters (Strotmann et al. 1995).
3.3.2 Agricultural Residues for Color Removal
Agricultural wastes are nonconventional low-cost adsorbents for metal adsorption,
being porous, and lightweight due to their fibrous existence. There are many
sustainable natural adsorbents that are commonly available globally, either at no
cost or at very low cost, as crop residues. Corncob shreds, wood chips and wheat
straw, cassava waste, coconut wastes, coir pith, and oil palm waste can be used for
their capacity to absorb individual colors and color mixtures. The retained agricultural substances were used instead of using chemicals to extract color from
dye-contaminated water to examine them as an economical and eco-friendly bioremediation process. Studies showed that a color removal can be achieved up to
70–75% using agro-waste in the removal of dye decolorization (Wong et al. 2004)
3.3.3 Chitin and Chitosan
Chitin is known as one of the important natural polymers. The two marine crustaceans, crabs and shrimp, are the principle sources for chitin. Chitosan is the derivative of chitin. While deacetylation of chitin is carried out to reach about 50%, chitin
becomes soluble in aqueous acidic media and is called as chitosan. Chitosan,
cationic polyelectrolyte, has been investigated for different industrial effluent treatment. It can act in the agglutination of colloidal particles due to its efficient
electrostatic action. Apart from acting as an auxiliary agglutinating polyelectrolyte,
chitin and chitosan are good adsorbents, able to efficiently remove azo dyes from
textile effluents (Mahajan 2004).
3.4 Integrated Approaches with Biotechnological
Interventions
3.4.1 Cell Factories and Whole-Cell Biocatalysts (WCBs)
The use of plants, fungi, microbes, etc. is primarily considered in bioremediation to
remove the contaminants. In recent bioremediation techniques, the enzymes and
210
K. Rajan et al.
bacteria (Seshadri et al. 1994). In this case, acidic medium-acting bacteria act on
organic substances, such as carbohydrates and fats. Such organic materials can be
converted into alcohols and other basic compounds through the catalysis of acidic
bacteria. These outcome products stimulate the acetogenic bacteria, which then
transform them into carbon dioxide and molecular hydrogen. Anaerobic reduction
of azo dyes can be an effective and economic treatment process for color removal
from textile wastewaters (Strotmann et al. 1995).
3.3.2 Agricultural Residues for Color Removal
Agricultural wastes are nonconventional low-cost adsorbents for metal adsorption,
being porous, and lightweight due to their fibrous existence. There are many
sustainable natural adsorbents that are commonly available globally, either at no
cost or at very low cost, as crop residues. Corncob shreds, wood chips and wheat
straw, cassava waste, coconut wastes, coir pith, and oil palm waste can be used for
their capacity to absorb individual colors and color mixtures. The retained agricultural substances were used instead of using chemicals to extract color from
dye-contaminated water to examine them as an economical and eco-friendly bioremediation process. Studies showed that a color removal can be achieved up to
70–75% using agro-waste in the removal of dye decolorization (Wong et al. 2004)
3.3.3 Chitin and Chitosan
Chitin is known as one of the important natural polymers. The two marine crustaceans, crabs and shrimp, are the principle sources for chitin. Chitosan is the derivative of chitin. While deacetylation of chitin is carried out to reach about 50%, chitin
becomes soluble in aqueous acidic media and is called as chitosan. Chitosan,
cationic polyelectrolyte, has been investigated for different industrial effluent treatment. It can act in the agglutination of colloidal particles due to its efficient
electrostatic action. Apart from acting as an auxiliary agglutinating polyelectrolyte,
chitin and chitosan are good adsorbents, able to efficiently remove azo dyes from
textile effluents (Mahajan 2004).
3.4 Integrated Approaches with Biotechnological
Interventions
3.4.1 Cell Factories and Whole-Cell Biocatalysts (WCBs)
The use of plants, fungi, microbes, etc. is primarily considered in bioremediation to
remove the contaminants. In recent bioremediation techniques, the enzymes and
210
K. Rajan et al.