389
presence of oxygen), anaerobic process (without oxygen), and coupled anaerobic–
aerobic process (Rai et al. 2005; Gupta and Suhas 2009). In aerobic process the final
products are water, biomass, and carbon dioxide, while in anaerobic process the
products are methane, biomass, and carbon dioxide (Ahmad et al. 2015). Biological
treatment offers considerable benefits such as (a) low cost, (b) eco-friendly, and (c)
less and non-toxic sludge formation (Gupta and Suhas 2009; Holkar et al. 2016).
According to the use of different kind of microorganism for the treatment of dyes,
the treatment process is divided in to three groups such as treatment by bacteria,
treatment by fungi/yeast, and treatment by algae. Bacteria are very popular microorganism for easy cultivation and rapid growing in dye treatment. In this process
mainly the azo dyes are degraded under aerobic, anaerobic, or facultative anaerobic
conditions (Ruan et al. 2019). Comparing with the anaerobic and facultative process, aerobic processes are responsible for the production of sludge (Holkar et al.
2016). In this process, bacteria degrades the azo dyes by reducing the azo bonds
with the help of azo-reductase enzymes at anaerobic environment (Ruan et al. 2019;
Holkar et al. 2016). Holkar et al. (2014) studied the anthraquinone-based reactive
blue 19 degradation up to 90% in 1 day, and Wang et al. 2009 found anthraquinonebased reactive black 5 up to 92% degradation under anaerobic condition within
120 h (Holkar et al. 2014; Wang et al. 2009). Babu et al. (2011) experimented the
removal of methyl red azo dye by biological treatment using bacteria with 95%
removal (Babu et al. 2011). Fungi and yeasts can be an attractive alternative for
dyes removal, due to their sustainability at any adverse condition and rapid bacterial
growth even at very low pH. The intra- and extracellular enzymes of fungi and yeast
help in metabolic activity to adjust in any environmental situation. These enzymes
degrade various types of dyes from the wastewater. These enzymes are manganese
peroxidase, lignin peroxidase, and laccase. White-rot fungal is the most popular
fungi used for azo dye degradation. White-rot fungi have four popular genera such
as Bjerkandera, Trametes, Phanerochaete, and Pleurotus. But, the major limitations
by fungi treatments are high hydraulic retention time for dye removal and the fungi
preservation in bioreactor (Ruan et al. 2019; Holkar et al. 2016). There is not so
much research works on dye removal by yeast treatment but in some cases, it is
found very effective. Yang et al. (2003) found the complete removal of reactive
black 5 by using two fungi, Penicillium geastrivorus and Umbelopsis isabelline,
within 16–48 h (Yang et al. 2003). Kwasniewska (1985) experimented that for the
removal of crystal violet, Rhodotorula rubra is found very useful (Kwasniewska
1985). Algae are very successful application for the treatment of dye presence in
wastewater. There are three different mechanisms for the dye degradation by algae.
Those are (1) dye consumption for algae growth, (2) conversion of dyes to various
intermediates or water and carbon dioxide, and (3) adsorption of chromophores on
algae. They are capable of both biodegradation as well as biosorption of dyes. Meng
et al. (2014) found that the azo-based acid red 27 dye removal by Shewanella algae
with high sodium chloride concentration and different humic acids or quinones
results in less toxic aromatic amines (Meng et al. 2014). Khataee et al. (2013) studied the degradation of azo-based color index basic red 46 by using Enteromorpha
species algae that eliminate azo dyes significantly. For biosorption, algal waste also
15 Remediation of Dyes from Industrial Wastewater Using Low-Cost Adsorbents
presence of oxygen), anaerobic process (without oxygen), and coupled anaerobic–
aerobic process (Rai et al. 2005; Gupta and Suhas 2009). In aerobic process the final
products are water, biomass, and carbon dioxide, while in anaerobic process the
products are methane, biomass, and carbon dioxide (Ahmad et al. 2015). Biological
treatment offers considerable benefits such as (a) low cost, (b) eco-friendly, and (c)
less and non-toxic sludge formation (Gupta and Suhas 2009; Holkar et al. 2016).
According to the use of different kind of microorganism for the treatment of dyes,
the treatment process is divided in to three groups such as treatment by bacteria,
treatment by fungi/yeast, and treatment by algae. Bacteria are very popular microorganism for easy cultivation and rapid growing in dye treatment. In this process
mainly the azo dyes are degraded under aerobic, anaerobic, or facultative anaerobic
conditions (Ruan et al. 2019). Comparing with the anaerobic and facultative process, aerobic processes are responsible for the production of sludge (Holkar et al.
2016). In this process, bacteria degrades the azo dyes by reducing the azo bonds
with the help of azo-reductase enzymes at anaerobic environment (Ruan et al. 2019;
Holkar et al. 2016). Holkar et al. (2014) studied the anthraquinone-based reactive
blue 19 degradation up to 90% in 1 day, and Wang et al. 2009 found anthraquinonebased reactive black 5 up to 92% degradation under anaerobic condition within
120 h (Holkar et al. 2014; Wang et al. 2009). Babu et al. (2011) experimented the
removal of methyl red azo dye by biological treatment using bacteria with 95%
removal (Babu et al. 2011). Fungi and yeasts can be an attractive alternative for
dyes removal, due to their sustainability at any adverse condition and rapid bacterial
growth even at very low pH. The intra- and extracellular enzymes of fungi and yeast
help in metabolic activity to adjust in any environmental situation. These enzymes
degrade various types of dyes from the wastewater. These enzymes are manganese
peroxidase, lignin peroxidase, and laccase. White-rot fungal is the most popular
fungi used for azo dye degradation. White-rot fungi have four popular genera such
as Bjerkandera, Trametes, Phanerochaete, and Pleurotus. But, the major limitations
by fungi treatments are high hydraulic retention time for dye removal and the fungi
preservation in bioreactor (Ruan et al. 2019; Holkar et al. 2016). There is not so
much research works on dye removal by yeast treatment but in some cases, it is
found very effective. Yang et al. (2003) found the complete removal of reactive
black 5 by using two fungi, Penicillium geastrivorus and Umbelopsis isabelline,
within 16–48 h (Yang et al. 2003). Kwasniewska (1985) experimented that for the
removal of crystal violet, Rhodotorula rubra is found very useful (Kwasniewska
1985). Algae are very successful application for the treatment of dye presence in
wastewater. There are three different mechanisms for the dye degradation by algae.
Those are (1) dye consumption for algae growth, (2) conversion of dyes to various
intermediates or water and carbon dioxide, and (3) adsorption of chromophores on
algae. They are capable of both biodegradation as well as biosorption of dyes. Meng
et al. (2014) found that the azo-based acid red 27 dye removal by Shewanella algae
with high sodium chloride concentration and different humic acids or quinones
results in less toxic aromatic amines (Meng et al. 2014). Khataee et al. (2013) studied the degradation of azo-based color index basic red 46 by using Enteromorpha
species algae that eliminate azo dyes significantly. For biosorption, algal waste also
15 Remediation of Dyes from Industrial Wastewater Using Low-Cost Adsorbents