et al. stated that cadmium and lead phytochelatin complexes, formation occurred in a
marine microalga when exposed to metal. Brown alga Fucus serratus was reported
for the accumulation and transformation of arsenic into arsenic compounds (Wasi
et al. 2013). Some research has shown that some of the species of fresh algae
(e.g. Scenedesmus platydiscus, S. quadricauda, Chlorella vulgaris and
S. capricornutum) have potential to uptake as well as degrade PAHs. Degradation
of azo dyes as carbon (C) and nitrogen (N) sources by the usage of C. vulgaris and
C. Pyrenoidosa was carried out, but degradation was based on the chemical structure
of the dyes. C. vulgaris, Lyngbyalagerlerimi, Nostoclincki, Oscillatoria rubescens,
Elkatothrix viridis and Volvox aureus were capable of decolorizing and removing
methyl red, orange II, G-Red, basic cationic and basic fuchsin from the effluent
waste. Some spp. of algae such as Chlorella, Anabaena inacqualis, Westiellopsis
prolifica, Stigeoclonium tenue and Synechoccus sp. can accumulate and remove
heavy metals, but the conditions of operation constrain the practical utilization of
these organisms. The microalga S. incrassatulus was observed for removal of
chromium (VI), cadmium (II) and copper (II) in continuous cultures. Green algae
were also observed bioremediation of heavy metals; C. Sorokiniana for chromium
(III) removal (Joutey et al. 2013). There are several possible hypotheses about the
mechanism of protozoa speeding up the bioremediation process of organic
pollutants, which generally includes the following six points:
1. The process to mineralize the nutrients that upgrades nutritional turnover.
2. Activation of bacteria that regulates the number of aged cells or excrete active
components.
3. Grazing should be selective which decreases competition of resources and space
for better growth of bacteria involved in degradation.
4. Physical hindrance can enhance overall O 2 content and the matter surface that is
biodegraded.
5. Direct biodegradation can secrete specialized biocatalyst involved in remediation.
6. Sym-metabolism is the process that offers energy and carbon source for the
degradation process carried out by bacteria (Joutey et al. 2013).
15.5 Microbial Enzymes Involved in Bioremediation
Enzymes act as a robust tool for sustaining pure environmental surroundings in
many methods. Enzymes are being used for the motive of bioremediation in various
industries, for example, oil, detergent, petroleum, agro-food, pulp and paper, textile,
leather, animal feed and especially chemical- and biochemical-based industries.
These biocatalysts are an efficient mode to maintain a clean environment by their
effective use in waste management (Ahuja et al. 2004). Enzymes may present several
advantages not only on traditional technologies but also on the bioremediation
process carried out by microbes. Enzymes are used under extreme conditions are
efficient by restricting the activity of microbes, not only when concentrations of
pollutants are very low but also when microbial predators or antagonists are present
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G. Kaur et al.
marine microalga when exposed to metal. Brown alga Fucus serratus was reported
for the accumulation and transformation of arsenic into arsenic compounds (Wasi
et al. 2013). Some research has shown that some of the species of fresh algae
(e.g. Scenedesmus platydiscus, S. quadricauda, Chlorella vulgaris and
S. capricornutum) have potential to uptake as well as degrade PAHs. Degradation
of azo dyes as carbon (C) and nitrogen (N) sources by the usage of C. vulgaris and
C. Pyrenoidosa was carried out, but degradation was based on the chemical structure
of the dyes. C. vulgaris, Lyngbyalagerlerimi, Nostoclincki, Oscillatoria rubescens,
Elkatothrix viridis and Volvox aureus were capable of decolorizing and removing
methyl red, orange II, G-Red, basic cationic and basic fuchsin from the effluent
waste. Some spp. of algae such as Chlorella, Anabaena inacqualis, Westiellopsis
prolifica, Stigeoclonium tenue and Synechoccus sp. can accumulate and remove
heavy metals, but the conditions of operation constrain the practical utilization of
these organisms. The microalga S. incrassatulus was observed for removal of
chromium (VI), cadmium (II) and copper (II) in continuous cultures. Green algae
were also observed bioremediation of heavy metals; C. Sorokiniana for chromium
(III) removal (Joutey et al. 2013). There are several possible hypotheses about the
mechanism of protozoa speeding up the bioremediation process of organic
pollutants, which generally includes the following six points:
1. The process to mineralize the nutrients that upgrades nutritional turnover.
2. Activation of bacteria that regulates the number of aged cells or excrete active
components.
3. Grazing should be selective which decreases competition of resources and space
for better growth of bacteria involved in degradation.
4. Physical hindrance can enhance overall O 2 content and the matter surface that is
biodegraded.
5. Direct biodegradation can secrete specialized biocatalyst involved in remediation.
6. Sym-metabolism is the process that offers energy and carbon source for the
degradation process carried out by bacteria (Joutey et al. 2013).
15.5 Microbial Enzymes Involved in Bioremediation
Enzymes act as a robust tool for sustaining pure environmental surroundings in
many methods. Enzymes are being used for the motive of bioremediation in various
industries, for example, oil, detergent, petroleum, agro-food, pulp and paper, textile,
leather, animal feed and especially chemical- and biochemical-based industries.
These biocatalysts are an efficient mode to maintain a clean environment by their
effective use in waste management (Ahuja et al. 2004). Enzymes may present several
advantages not only on traditional technologies but also on the bioremediation
process carried out by microbes. Enzymes are used under extreme conditions are
efficient by restricting the activity of microbes, not only when concentrations of
pollutants are very low but also when microbial predators or antagonists are present
436
G. Kaur et al.