Biology Reference
In-Depth Information
the PUFA, C
18:2ω3 ,
C
18:3ω3
and C
20:5ω3
both under aerobic and anaerobic
conditions at 15°C and 25°C. High prevalence of PUFA producing
bacteria in arctic invertebrates has been observed.
More than 100 bacterial
strains including
Pseudomonasa
and
Vibrio
spp., capable of producing
DHA and EPA (eicosapentaenoic acid), were isolated from arctic and
sub-arctic invertebrates and also from some fi sh species (Jostenseri and
Landfaid, 1997). Recently advanced molecular techniques have enhanced
the prospects of isolation and identifi cation of PUFA from marine
microorganisms (Nichols, 2003). In addition to bacteria, fungi could also
provide PUFA.
A growing number of marine fungi are the sources of novel and potentially
life-saving bioactive secondary metabolites (Cole and Schweikert, 2003).
Filamentous fungi have long been used by the fermentation industry for
the production of metabolites including antibiotics and enzymes. Along
with developments in molecular genetics, research on bioprocessing
technologies may have a competitive advantage for production of
enzymes, healthcare products including generic biopharmaceuticals from
fungi (Wang et al., 2005b; Bhadury et al., 2006). A process for growing
fungi,
Schizochytrium
and
Thraustochytrium
spp., and for production of
PUFA has been patented. These fungi were grown in fermentation medium
containing non-chloride sodium salts, in particular, sodium sulfate. The
process produced fungi with a cell aggregate size that was useful for the
production of feeds for use in aquaculture (Barday, 2006).
Cultivation and Genomics of Marine Microorganisms
Most products obtained from microbial growth are formed as secondary
metabolites. Therefore, optimization of culture conditions is essential
for maximum recovery of these compounds. The majority of marine
microbes cannot be cultured under artifi cial laboratory conditions and
hence have posed problems in detailed taxonomical and physiological
characterization. Nevertheless, interesting laboratory conditions have been
created for cultivation of microorganisms which are adapted to extreme
environments (Antranikian et al., 2005). Recent research extending the
last two decades has provided genomics, post-genomic cloning, protein
expression and other gene techniques for production of these metabolites,
opening up new possibilities for the exploration of pathways responsible
for the synthesis of metabolites of biotechnological interest. The function
of the majority of genes within the sequenced marine genomes is not
well understood. In order to assign potential functions to the genes
of a genome, functional genome analysis techniques are used. These
techniques include the expression profi ling of the whole set of genes by
using genomic DNA arrays and
/
or proteomics. These techniques are not
