Molecular Plant Breeding 2016, Vol.7, No.9, 1-16
http:// mpb.biopublisher.ca
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roles in biotechnology such as production of drugs
and enzymes (Archer et al., 2008). Fungi can be
cultured easily and hence they can be used in
microbiological, genetic and molecular research
(Hoffmeister and Keller, 2007).
Aspergillus is wide spread fungus in nature, including
soil, colonizing plant materials and decomposing
agricultural crops (Varga et al., 2004) as well as most
common air borne fungi (Gregory, 1973). Many
species of Aspergillus are causative agents of food
decay and others are used in fermentation industry
(Bennett & Klich, 1992). Aspergillus niger is a potent
source of enzyme production and has been exploited
commercially for the production of different
extracellular enzymes (Kitani and Olive, 1967). Based
on the secretion capacities, many efforts have also
been undertaken to develop
A. niger
as a producer of
heterologous proteins which include hydrolytic
enzymes (Joosten et al., 2003). Fungi have great
potential to decompose wastes and this is the reason
why scientists are studying fungi at molecular level
for different enzymes genes (Shimosaka et al., 1996).
The
A. niger
genome size is 36 Mb and contains over
14,000 genes (Bennett and Klinch, 1997). Sordaria
macrospora is a filamentous ascomycete and its
genome has been sequenced because it has been used
as model organism in fungal developmental studies
and in meiosis analysis, (Nowrousian et al., 2012); its
genome size is 39.8 Mb containing 7 chromosomes
(Teichert et al., 2012). Sordaria fimicola and
S.
macrospora
are closely related to the N. crassa,
however the natural habitat of N. crassa is burned
vegetation and soil all over the world (Esser, 1982),
while Sordaria species grow on herbivore dung in
temperate climate (Jacobson et al., 2004). Sordaria
fimicola strains have not been evaluated earlier for
different enzymes production, therefore enzyme
production in S. fimicola were included in the current
research.
3.1 Laccase enzyme
Laccases (EC 1.0.3.2) have oxido-reductase function
and used in many industrial processes as biocatalyst
(Lee et al., 2004). This enzyme has several usages in
different industrial processes including biopulping,
biobleaching and treatment of industrial waste water;
textile dye discoloration and a wide range of other
applications, hence the most important biocatalyst in
fungal biotechnology (Schauer and Borriss, 2004;
Bourdais et al., 2012).
Couto and Toca- Herrera,
(2007) described that laccases are capable of oxidizing
phenolic and non-phenolic aromatic compounds. This
enzyme is used for finishing and dying of textile,
making wine cork and in tooth whitening items
(Xu-Feng, 2005). Laccase is monomers having a
molecular mass in the range of 40-130 kDa with a
covalently linked carbohydrate content of 10-25 % in
fungi and 20-45 % in plants (Claus, 2003). The
carbohydrate moiety typically consists of mannose,
N-acetylglucosamine and galactose that may be
helpful to maintain the stability and configuration of
enzyme (Kunamneni et al., 2008). Laccase from N.
crassa is an inducible secretory enzyme and the
production of laccase is repressed in vegetative
structures of fungus, but can be induced by treatment
with low concentrations of cycloheximide (Tamaru
and Inoue, 1989). Other fungi that have laccase
activity include Trichoderma (wood-decaying
ascomycetes) and Botryosphaeria (Vasconcelos et al.,
2000; Hatakka, 2001; Pointing et al., 2005). Laccase
has ability to oxidize compounds like polyphenols,
cyclic diamines, methoxy substituted phenols and
other compounds (Baldrian, 2006). In case of lower
fungi such as Zygomycetes and Chytridiomycetes
production of this enzyme has never been revealed
(Morozova et al., 2007). Due to higher oxidation
reduction potential (+800 mV of the fungal laccase
enzymes as compared to bacterial and plant laccases),
these fungal enzymes have more application in
biotechnology (Thurston, 1994) for their use as
processing aids in food industry (Minussi et al., 2002,
Minussi et al., 2007).
Genes encoding laccase enzymes have been studied in
different filamentous fungi like
A. niger
,
A. oryzae
and
T. reesei
(Couto and Toca-Herrera, 2007;
Hoffmeister and Keller, 2007). Laccases are
copper-containing enzymes with several biological
applications (Mayer and Staple, 2002). A lot of fungi
possess many endogenous genes whose expression is
tightly regulated (FeRNA´ndez-Larrea and Stahl,
1996). Laccases play an important role in the
degradation of lignin as reported in Basidiomycetes by
Crestini et al., (2003). FeRNA´ndez-Larrea and Stahl,
(1996) described that exposure to phenolic
