Environmental Engineering Reference
In-Depth Information
highest temperature, is an example of polyextremophiles at high temperature and
high pressure extremes (Marteinsson et al.,
1999
). Most of deep sea bacteria are
adapted to low temperature (2
110 MPa) as polyex-
tremophiles. Soda lakes are the source of haloalkaliphilic microorganisms like
Natronobacterium gregoryi which can thrive in high pH and high salt concentra-
tions (Tindall et al.
1984
). These are some examples of poly environmental
extremes which were explored for polyextremophilic life. Culture independent
methods revealed microbial life in the environmental extremes wherein we don
4
°
C) and high pressure (50
-
-
t
have expectation of life (Antunes et al.
2011
; Stock et al.
2012
). This helps us to
understand the true shape of habitable space on earth.
We are indirectly bene
'
tted by extremophilic and polyextremophilic microor-
ganisms which are used in biotechnology and bioremediation (Rothschild and
Manicelli
2001
). Many of industrial wastes have harsh conditions which make
extremophiles and polyextremophiles a good choice for their treatment before
releasing them into the environment. Understanding the physical, geochemical and
biological limits of life is an emerging biotechnological interest in view of appli-
cations of extremophiles, polyextremophiles and their biomolecules in industrial
processes and waste treatments (Podar and Reysenbach
2006
; Taylor et al.
2012
).
Textile colored ef
uents wherein
microorganisms, which are used for their decolorization, are subjected to a harsh
condition due to the high salinity, alkaline pH and high temperature of the efuents
(McMullan et al.
2001
; Kandelbauer and Guebitz
2005
). Extremophilic microor-
ganisms, which are naturally adapted to this harsh condition, are a perfect choice for
treatment of the wastewaters. As these ef
uent
is one of the complex industrial ef
uents have a combination of environ-
mental extremes, polyextremophilic microorganisms attracted the attention of sci-
entists and became the subject of scienti
nding new highly capable
microorganisms for textile colored wastewater treatment.
There are some examples of polyextremophilic microorganisms which have
been able to decolorize textile wastewaters. Four fungal strains, isolated from
environmental samples, were assayed for their ability for Brown GR dye decol-
orization. These strains belonged to the genus Aspergillus which showed the
highest decolorization ef
c scrutiny for
ciency at pH 4 and 2 % (w/v) NaCl concentration (Singh
et al.
2013
).
A moderately halophilic and alkalitolerant bacterium was isolated from the salty
ef
uents of textile industries in central Iran with remarkable azo dyes decolorizing
ability over wide ranges of pH (7
11) and temperature (25
45
°
C), in presence of
-
-
NaCl and Na
2
SO
4
(0.5
1.5 M) under both anaerobic and aerobic conditions
(Fig.
2
). According to 16S rDNA sequence similarity analysis, this strain belonged
to the genus Halomonas with the highest similarity to Halomonas axialensis
(Pourbabaee et al.
2011
).
Bacillus sp. strain SF was isolated from wastewater drain of textile
-
nishing
°
company and showed growth at pH 9.3
C temperature. This
alkali-thermophilic microorganism has the ability of azo dye decolorization. An
-
10 and 60
-
65
Search WWH ::
Custom Search