The marine environment is a rich source for naturally occurring antioxidants and pigments with a
diverse range of microorganisms producing a unique
and valuable resource. The potential for the discovery of new pigments and other additives which
can be used to replace some of the existing artificial
additives currently being used in the food industry is
significant.
Sunscreens
The continuous exposure of marine organisms to
strong sunlight has resulted in some, primarily the
macro- and microalgae, evolving compounds which
provide a very good screen against ultraviolet (UV)
light. These organisms have the ability to synthesize
small organic molecules, called mycosporine-like
amino acids (MAAs), which are capable of absorbing
UV light very efficiently and thus prevent DNA
damage. Over 20 different MAAs occur in nature
with a wide range of marine organisms utilizing
them, including corals, anemones, limpets, shrimp,
sea urchins, and some vertebrates including fish and
fish eggs. MAAs are widely distributed across the
marine environment; however, they can only be
synthesized by certain types of bacteria or algae. For
example, red seaweeds and some bloom-forming
phytoplankton species are a particularly rich source
of MAAs. Studies have revealed that in addition to
their screening ability, some MAAs, such as mycosporine-glycine, have antioxidant properties. The
ability of naturally occurring compounds such as
MAAs to act as effective sunscreens has resulted in
some interest from the commercial sector as to the
value of these compounds in creams and cosmetics.
Biocatalysis
The ability of enzymes to synthesize complex chiral
molecules with high efficiency and precision is of
considerable interest within the pharmaceutical and
chemical industries and marine bacteria present a
new source for novel enzymes with not only unusual
synthetic properties but also potentially valuable
catalytic and structural properties. This arises from
the ability of marine bacteria to grow under extreme
conditions such as high and low temperature, high
pressure (extreme depth), high salinity, and extremes
of pH. This has opened up the potential to isolate
naturally occurring small molecules which are difficult to synthesize in the laboratory but which could
be of value in synthetic organic chemistry as intermediates. The existence of a large number of potentially novel enzymes in these same organisms
which are capable of performing diverse chemical
modifications not readily amenable by standard
chemical synthesis also opens the route to novel
chemical modification of synthetic molecules using
biocatalysis and biotransformation.
Growth of microbes under these extreme conditions has led to proteins which possess different
temperature optima and improved stability, which
has been exploited in the development of new processes and methods such as the polymerase chain
reaction, a method for amplifying specific fragments
of DNA, and which depends on a thermostable
DNA polymerase isolated from a thermophilic
microorganism. It has been suggested that enzymes
which display high salt tolerance may be of value in
the development of enzyme reactions to be performed in organic solvents as they appear to be less
prone to denaturing under dehydrating conditions.
Marine bacteria make up the largest potential
single source of novelty in the world’s oceans and of
these the major component are the actinobacteria
which includes the actinomycetes. Actinomycetes are
readily isolated from the marine environment and
consequently are the best studied of the actinobacteria but the other more difficult to culture
members are now being identified using advanced
culturing and molecular techniques. The actinomycetes in particular hold the promise of tremendous
diversity and to date have been underexploited.
Terrestrial actinomycetes are responsible for about
half of the known bioactive molecules isolated from
natural sources to date and include antibiotics,
antitumor compounds, immunosuppressants, and
novel enzymes. Consequently, the isolation of new
organisms from the environment and their analysis
for novel metabolites has been a cornerstone in drug
discovery. In recent years, however, terrestrial organisms have divulged less novelty than before, and
advances in microbiology and genetics have now
made the exploitation of marine-derived actinomycetes more attractive. The recognition that the
world’s oceans are rich in biological diversity and
that extreme environmental conditions (e.g., high
pressure and temperature at deep-sea hydrothermal
vents) have not repressed the development of
organisms to form distinct ecological niches suggests
that these habitats will be a rich source of chemical
novelty.
Although much emphasis has been placed on isolating organisms from extreme environments in the
search for novel biocatalysts, the general marine environment should not be ignored. Both micro- and
macroalgae have been demonstrated to produce novel
enzymes with possible applications in biocatalysis
such as the haloperoxidases, enzymes capable of
116 MARINE CHEMICAL AND MEDICINE RESOURCES
diverse range of microorganisms producing a unique
and valuable resource. The potential for the discovery of new pigments and other additives which
can be used to replace some of the existing artificial
additives currently being used in the food industry is
significant.
Sunscreens
The continuous exposure of marine organisms to
strong sunlight has resulted in some, primarily the
macro- and microalgae, evolving compounds which
provide a very good screen against ultraviolet (UV)
light. These organisms have the ability to synthesize
small organic molecules, called mycosporine-like
amino acids (MAAs), which are capable of absorbing
UV light very efficiently and thus prevent DNA
damage. Over 20 different MAAs occur in nature
with a wide range of marine organisms utilizing
them, including corals, anemones, limpets, shrimp,
sea urchins, and some vertebrates including fish and
fish eggs. MAAs are widely distributed across the
marine environment; however, they can only be
synthesized by certain types of bacteria or algae. For
example, red seaweeds and some bloom-forming
phytoplankton species are a particularly rich source
of MAAs. Studies have revealed that in addition to
their screening ability, some MAAs, such as mycosporine-glycine, have antioxidant properties. The
ability of naturally occurring compounds such as
MAAs to act as effective sunscreens has resulted in
some interest from the commercial sector as to the
value of these compounds in creams and cosmetics.
Biocatalysis
The ability of enzymes to synthesize complex chiral
molecules with high efficiency and precision is of
considerable interest within the pharmaceutical and
chemical industries and marine bacteria present a
new source for novel enzymes with not only unusual
synthetic properties but also potentially valuable
catalytic and structural properties. This arises from
the ability of marine bacteria to grow under extreme
conditions such as high and low temperature, high
pressure (extreme depth), high salinity, and extremes
of pH. This has opened up the potential to isolate
naturally occurring small molecules which are difficult to synthesize in the laboratory but which could
be of value in synthetic organic chemistry as intermediates. The existence of a large number of potentially novel enzymes in these same organisms
which are capable of performing diverse chemical
modifications not readily amenable by standard
chemical synthesis also opens the route to novel
chemical modification of synthetic molecules using
biocatalysis and biotransformation.
Growth of microbes under these extreme conditions has led to proteins which possess different
temperature optima and improved stability, which
has been exploited in the development of new processes and methods such as the polymerase chain
reaction, a method for amplifying specific fragments
of DNA, and which depends on a thermostable
DNA polymerase isolated from a thermophilic
microorganism. It has been suggested that enzymes
which display high salt tolerance may be of value in
the development of enzyme reactions to be performed in organic solvents as they appear to be less
prone to denaturing under dehydrating conditions.
Marine bacteria make up the largest potential
single source of novelty in the world’s oceans and of
these the major component are the actinobacteria
which includes the actinomycetes. Actinomycetes are
readily isolated from the marine environment and
consequently are the best studied of the actinobacteria but the other more difficult to culture
members are now being identified using advanced
culturing and molecular techniques. The actinomycetes in particular hold the promise of tremendous
diversity and to date have been underexploited.
Terrestrial actinomycetes are responsible for about
half of the known bioactive molecules isolated from
natural sources to date and include antibiotics,
antitumor compounds, immunosuppressants, and
novel enzymes. Consequently, the isolation of new
organisms from the environment and their analysis
for novel metabolites has been a cornerstone in drug
discovery. In recent years, however, terrestrial organisms have divulged less novelty than before, and
advances in microbiology and genetics have now
made the exploitation of marine-derived actinomycetes more attractive. The recognition that the
world’s oceans are rich in biological diversity and
that extreme environmental conditions (e.g., high
pressure and temperature at deep-sea hydrothermal
vents) have not repressed the development of
organisms to form distinct ecological niches suggests
that these habitats will be a rich source of chemical
novelty.
Although much emphasis has been placed on isolating organisms from extreme environments in the
search for novel biocatalysts, the general marine environment should not be ignored. Both micro- and
macroalgae have been demonstrated to produce novel
enzymes with possible applications in biocatalysis
such as the haloperoxidases, enzymes capable of
116 MARINE CHEMICAL AND MEDICINE RESOURCES