Microbial Degradation of Basic Dyes in Wastewaters - Microbial Degradation of Synthetic Dyes in Wastewaters - page 94

these enzymes is often induced by limited nutrient levels (mostly C or N). Under
submerged fermentation, the production of LiP and MnP is generally optimal at
high aeration levels, but repressed by agitation. The laccase production is often
enhanced by agitation, aromatic compounds and organic solvent (Galhaup et al.
2002 ), and normally more than one isoforms of LME are expressed by different
taxa and culture conditions. These features are important from a process design
perspective and for optimization of fungal treatment of dye-containing ef uents. In

reality, many WRF produced these oxidoreductases (LiP, MnP) in low quantities
which are dependent on metal ions and the co-substrate hydrogen peroxide, and
thus have not been able to reach large-scale commercial applications (Wesenberg
et al. 2003 ). Table 3 describes the details on oxidoreductase enzymes produced by
different white rot fungi and other fungi involved in decolorization and/or bio-
degradation of basic dyes.
Phanerochaete chrysosporium was the

rst widely investigated WRF capable of
biodegradation of various pollutants and industrial dye ef uents (Glenn and Gold

1983 ) and was considered as a model WRF in many research studies carried out till
now (Wesenberg et al. 2003 ). This fungus produces lignin peroxidase (LiP) and
manganese peroxidase (MnP) (Faraco et al. 2009 ). Later, several white rot fungi,
such as Pleurotus ostreatus (Shin and Kim 1998 ), Pleurotus calyptratus (Eichler-
ova et al. 2006a ), Trametes versicolor (Hein ing et al. 1997 ; Casas et al. 2009 ;

Pazarlioglu et al. 2010 ), Ischnoderma resinosum (Eichlerova et al. 2006b ), Bjer-
kandera adusta (Robinson et al. 2001b ; Eichlerova et al. 2007 ), Irpex lacteus
(Novotny et al. 2000 ) and Dichomites squalens (Eichlerova et al. 2006c ) were
investigated in details for dye degradation. Particularly, laccases secreted by Pyc-
noporus sanguineus (Pointing and Vrijmoed 2000 ) and Trametes sp. SQ01 (Yang
et al. 2009 ) demonstrated their ability to decolorize azo, triphenylmethane and
anthraquinonic dyes. Novotny et al. ( 2004 ) studied the biodecolorization of many
synthetic dyes by using a white rot fungus, Irpex lacteus and 96 % of decolorization
of Bromophenol blue was observed within 2 weeks. Papinutti et al. ( 2006 ) reported
that Fomes sclerodermeus could decolorize Malachite green-adsorbed wheat bran
during solid state fermentation which may be due to the effect of laccase or Mal-
achite green reductase activity. Jasinska et al. ( 2012 ) demonstrated that Malachite
green decolorization by the submerged culture of Myrothecium roridum IM 6482
was due to stimulation of laccase production. In addition, lignin peroxidase from
different bacterial sources, such as Kocuria rosea MTCC 1532 (Parshetti et al.
2006 ), Pseudomonas desmolyticum NCIM 2112 (Kalme et al. 2007 ), Rhizobium
radiobacter MTCC 8161 (Parshetti et al. 2009 ) and Acinetobacter calcoaceticus
NCIM 2890 (Ghodake et al. 2009 ) has been reported to be involved in dye
decolorization. Several anaerobic intestinal micro ora (Henderson et al. 1997 ) and

waterborne pathogenic mycobacterial strains (Jone and Flakinham 2003 ) were
found to perform decolorization of Malachite green and Crystal violet to their
respective leuco derivatives through enzymatic reduction. However, the enzymes
involved in the reduction process have not yet been characterized. A triphenyl-
methane reductase (TMR), that catalyzed the reduction of triphenylmethane dyes,
was synthesized by Citrobacter sp. strain KCTC 18061P which was puri

ed,