8 Marine Biotechnology
299
SIGEX is designed to select the clones that harbour catabolic genes induced by various substrates coupled with GFP and sorted by fluorescence-activated cell sorting
(FACS). This high throughput method was successfully applied to isolate aromatichydrocarbon-induced genes from a metagenomic library. In spite of its advantages,
it suffers from several limitations (such as the orientation of genes in the cloning
vector or genes with terminators and consequently poor yield with large inserts)
(De Lorenzo 2005, Yun and Ryu 2005).
The search for various biocatalysts from natural sources can be facilitated by the
addition of various substrates to the environment to enrich the microbial community
in strains able to degrade these substrates. In the same manner, an approach that
might considerably reduce the sequencing effort required by metagenomics would
be to sort the DNA of interest from the bulk DNA. Considerable progress has been
done in that direction in the last years using stable isotope probing (SIP). Applied to
lake sediments, targeting specifically methylothrophs (metabolism of organic compounds containing no carbon-carbon bonds), through 13 C-labeled C 1 compounds,
it was possible to extract DNA from the microcosms and separate the labelled
fraction containing the genes of interest (Kalyuzhnaya et al. 2008). This method,
though developed mainly for analysis of the functions of the different components
of a microbial community, can be used in metagenomics of complex communities
to enrich DNA fractions to be sequenced in a define gene profile and therefore,
contribute to biotech research.
8.4 Contribution of Marine Biotechnology to the Discovery
of Natural Products, Novel Pharmaceuticals
and White Technology
Numerous natural products and enzymes have been discovered in marine organism; some examples are given here from bacteria, archaea, marine fungi, metazoans,
virus and algae. This is by no means a complete listing of all products found in the
marine environment, only a few products are indicated from each group to demonstrate the potential of the different taxa. The absence of certain phylogenetic groups
should be seen as an indication that an important unexplored metabolic diversity
may be found, for example, in the amoebozoa, rhizaria and among the excavates.
8.4.1 Viruses
Marine viruses represent perhaps the greatest untapped biotechnological resource
on the planet. With an average of 10 6 viruses/ml of sea water and an estimated 10 30
in our oceans, this is a massively under-studied and under-utilised resource (Suttle
2007). Historically, enzyme and natural product discovery has depended upon
culture dependent approaches, approaches that are more complicated for viruses
which require a suitable host for propagation. Thus, the advent of the metagenomic
299
SIGEX is designed to select the clones that harbour catabolic genes induced by various substrates coupled with GFP and sorted by fluorescence-activated cell sorting
(FACS). This high throughput method was successfully applied to isolate aromatichydrocarbon-induced genes from a metagenomic library. In spite of its advantages,
it suffers from several limitations (such as the orientation of genes in the cloning
vector or genes with terminators and consequently poor yield with large inserts)
(De Lorenzo 2005, Yun and Ryu 2005).
The search for various biocatalysts from natural sources can be facilitated by the
addition of various substrates to the environment to enrich the microbial community
in strains able to degrade these substrates. In the same manner, an approach that
might considerably reduce the sequencing effort required by metagenomics would
be to sort the DNA of interest from the bulk DNA. Considerable progress has been
done in that direction in the last years using stable isotope probing (SIP). Applied to
lake sediments, targeting specifically methylothrophs (metabolism of organic compounds containing no carbon-carbon bonds), through 13 C-labeled C 1 compounds,
it was possible to extract DNA from the microcosms and separate the labelled
fraction containing the genes of interest (Kalyuzhnaya et al. 2008). This method,
though developed mainly for analysis of the functions of the different components
of a microbial community, can be used in metagenomics of complex communities
to enrich DNA fractions to be sequenced in a define gene profile and therefore,
contribute to biotech research.
8.4 Contribution of Marine Biotechnology to the Discovery
of Natural Products, Novel Pharmaceuticals
and White Technology
Numerous natural products and enzymes have been discovered in marine organism; some examples are given here from bacteria, archaea, marine fungi, metazoans,
virus and algae. This is by no means a complete listing of all products found in the
marine environment, only a few products are indicated from each group to demonstrate the potential of the different taxa. The absence of certain phylogenetic groups
should be seen as an indication that an important unexplored metabolic diversity
may be found, for example, in the amoebozoa, rhizaria and among the excavates.
8.4.1 Viruses
Marine viruses represent perhaps the greatest untapped biotechnological resource
on the planet. With an average of 10 6 viruses/ml of sea water and an estimated 10 30
in our oceans, this is a massively under-studied and under-utilised resource (Suttle
2007). Historically, enzyme and natural product discovery has depended upon
culture dependent approaches, approaches that are more complicated for viruses
which require a suitable host for propagation. Thus, the advent of the metagenomic