Environmental Engineering Reference
In-Depth Information
production of azo reductase (Salah Uddin et al.
2007
). Decolorization of Acid Black
210 by a Vibrio harveyi TEMS1, isolated from coastal seawater of Turkey, has been
also studied. Decolorization studies were performed in medium with 5 g l
−
1
NaCl
concentration (Ozdemir et al.
2008
). Shewanella algae and Shewanella maris
avi,
isolated from marine environments, demonstrated better azo dye decolorization
ability as compared to their strains isolated from non-saline sources. S. algae and S.
maris
avi are able to decolorize amaranth dye at up to 100 (g l
−
1
) NaCl or Na
2
SO
4
(Liu et al.
2013
). The moderately halotolerant bacterial strain Bacillus
rmus
effectively decolorized Polar red B (an azo dye) in synthetic saline wastewater
medium. Decolorization occurred in a wide range of sodium chloride (1
6 %, w/v),
-
100 mg l
−
1
) and at pH range of 6
dye (5
10 after 24 h of incubation. Cell
immobilization studies of this strain clearly indicated that color removal was
signi
-
-
cantly higher in immobilized cell systems especially at salt concentrations
higher than 4 % (Ogugbue et al.
2011
).
Thermophilic microorganisms are a group of extremophiles which are able to
thrive and grow at high temperatures from 45 to 122
C. Many of thermophiles
belong to the domain Archaea (Brock
1967
). Thermophilic microbes are among
well studied extremophiles, as their enzymes are well suited for industrial processes
(Prieur
2007
). Based on advantages of these organisms, natural and arti
°
cial hot
environments have been widely screened for novel thermophilic microorganisms
and bioactive compounds (Torkamani et al.
2008
; Kublanov et al.
2009
). The
biggest disadvantage of such microorganisms for biotechnological application is
higher equipment corrosion and liquid evaporation which haven
t been properly
tackled for large scale operations. Eight thermophilic consortia were separated from
Spain
'
s northwest hot springs with the ability of Reactive Black 5 dye decolor-
ization at 65
'
C. From these consortia, 3 bacterial strains were isolated which
showed closest similarity to Anoxybacillus pushchinoensis, Anoxybacillus kam-
chatkensis and Anoxybacillus
°
n et al.
2010
). Anoxybacillus rupiensis is a thermophilic bacterium which was isolated from
hot springs of Maharashtra state in India. When reddish-black ef
avithermus (Deive et al.
2010
; Sanrom
á
uents of dyeing
unit of a textile factory in Aurangabad, Maharashtra with the pH of 10.5 were
subjected to this bacterium for decolorization, the results showed 75 % decolor-
ization through degradation at 60
°
C in eight days (Gursahani and Gupta
2011
).
Batch assays of mesophilic (30
C) anaerobic consortia
were studied for decolorization of Reactive Red 2 and Reactive Orange 14 azoic
dyes. The contribution of fermentative and methanogenic microorganisms in both
temperatures was also evaluated. Results revealed that the application of thermo-
philic anaerobic treatment was an interesting option for the reductive decolorization
of azo dyes compared to mesophilic conditions (Dos Santos et al.
2005
). Two
facultative anaerobic bacteria consortia and a bacterial isolate DTB showed the
ability of decolorization of textile colored discharge ef
°
C) and thermophilic (55
°
uents. Both cultures were
°
able to grow and decolorize the ef
C.
These isolated bacteria can be used for textile colored wastewater treatment which
is normally discharged at elevated temperatures (Banat et al.
1997
).
uents at elevated temperatures up to 60
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