introducing halogen atoms into metabolites. For example, two species of tropical red macroalgae produce halogenated compounds as a defense against
predators and such compounds are being tested for
medical applications. The availability of haloperoxidases with different catalytic functions would be of
use in generating new types of halogenated molecules
for the chemical and pharmaceutical industries.
The realization that viruses are the most abundant
biological agents in the marine environment and the
discovery of highly diverse, ancient, giant viruses
with genomes comparable in size to the smallest
microbes opens up new sources of genetic diversity.
Current indications are that the oceans contain a
wide variety of both DNA and RNA viruses with
survival strategies which mimic those of terrestrial
viruses yet these marine viruses encode a great many
proteins of unknown function. Most marine viruses
are assumed to be bacteriophages because virus
particles are most commonly detected in the vicinity
of bacteria, and bacteria are the most abundant organisms in the oceans.
Recent studies have revealed that marine viruses
encode unexpected and novel proteins which would
not be expected to occur within a virus genome. For
example, the giant algal viruses have been shown to
encode novel glycosylases, potassium pumps, and a
pathway for the synthesis of complex sphingolipids.
This biochemical diversity indicates that marine viruses could be a rich source for exploitation in the
future for new types of carbohydrate and lipid as
well as new proteins and enzymes.
Bioremediation
Pollution of the marine environment is a growing
concern particularly with the continuous discharge
of both industrial and domestic waste into rivers and
estuaries leading to concerns about the impact such
pollution could have on long-term human health.
The discovery of marine microorganisms capable
of detoxifying heavy metals and utilizing complex
hydrocarbons as an energy source has provided a
new impetus to develop natural solutions to the
problems of environmental pollution. However, it
should be remembered that toxic substances are not
the only causes of marine distress and that the utilization of fertilizers and the disposal of sewage can
also result in an imbalance in the marine ecology,
resulting in the formation of large, often toxic, algal
blooms which although not always a direct threat to
human health do lead to widespread ecological
damage. Thus, the discovery of microbes capable of
growing in the presence of high concentrations of
ammonia could be of value in the treatment of
wastewater, and an understanding of the anaerobic
oxidation of ammonia could lead to the development
of new chemical processes. The same organisms also
possess unusual metabolic intermediates such as hydrazine and produce unusual lipids which could also
be of value in the search for new chemical
intermediates.
Heterocyclic molecules containing sulfur, nitrogen,
and oxygen are among the most potent pollutants
and inevitably contaminate the marine environment
to a considerable extent. The use of microbes to
degrade and detoxify such compounds is gaining
considerable interest as a process which is environmentally friendly and would represent a long-term
solution to removing heterocyclic contaminants.
A particularly rich source of such organisms is the
marine environment where growth in close proximity to sulfur-rich hydrothermal vents or adjacent to
hydrocarbon (oil) seeps on the ocean floor has produced a plethora of microorganisms with metabolisms adapted to the utilization of a wide variety of
carbon-, nitrogen-, and sulfur-based chemistries.
Again, these organisms are also a very rich source of
enzymes with previously unknown characteristics
such as unusual substrate specificity, which could be
of great value to the chemicals industry where they
could be utilized in the production of new or
difficult-to-synthesize compounds because they can
perform reactions which are difficult to duplicate
using traditional synthetic chemistry methods.
Microbial Fuel Cells and Biofuels
The use of marine organisms to produce fuels has also
been proposed. The generation of electricity through
the degradation of organic matter has recently been
demonstrated to occur in marine sediments and may
be mediated by complex communities of marine
microorganisms. These organisms degrade complex
organic matter such as carbohydrates and proteins to
simpler molecules such as acetate which are then used
by electricity-generating bacteria to reduce metals
such as iron and manganese. By replacing the naturally occurring metals with an anode these bacteria,
under anoxic conditions, will supply the electrons
needed to produce an electric current to a cathode
linked to the anode by wires and exposed to the
oxygen in the water column. It has been suggested
that this type of system could be used to supply the
electricity needed to operate equipment in regions
where access is difficult and so eliminate the need
to replace batteries. Microbial fuel cells would be selfsustaining, would not require the preprocessing of
MARINE CHEMICAL AND MEDICINE RESOURCES 117
predators and such compounds are being tested for
medical applications. The availability of haloperoxidases with different catalytic functions would be of
use in generating new types of halogenated molecules
for the chemical and pharmaceutical industries.
The realization that viruses are the most abundant
biological agents in the marine environment and the
discovery of highly diverse, ancient, giant viruses
with genomes comparable in size to the smallest
microbes opens up new sources of genetic diversity.
Current indications are that the oceans contain a
wide variety of both DNA and RNA viruses with
survival strategies which mimic those of terrestrial
viruses yet these marine viruses encode a great many
proteins of unknown function. Most marine viruses
are assumed to be bacteriophages because virus
particles are most commonly detected in the vicinity
of bacteria, and bacteria are the most abundant organisms in the oceans.
Recent studies have revealed that marine viruses
encode unexpected and novel proteins which would
not be expected to occur within a virus genome. For
example, the giant algal viruses have been shown to
encode novel glycosylases, potassium pumps, and a
pathway for the synthesis of complex sphingolipids.
This biochemical diversity indicates that marine viruses could be a rich source for exploitation in the
future for new types of carbohydrate and lipid as
well as new proteins and enzymes.
Bioremediation
Pollution of the marine environment is a growing
concern particularly with the continuous discharge
of both industrial and domestic waste into rivers and
estuaries leading to concerns about the impact such
pollution could have on long-term human health.
The discovery of marine microorganisms capable
of detoxifying heavy metals and utilizing complex
hydrocarbons as an energy source has provided a
new impetus to develop natural solutions to the
problems of environmental pollution. However, it
should be remembered that toxic substances are not
the only causes of marine distress and that the utilization of fertilizers and the disposal of sewage can
also result in an imbalance in the marine ecology,
resulting in the formation of large, often toxic, algal
blooms which although not always a direct threat to
human health do lead to widespread ecological
damage. Thus, the discovery of microbes capable of
growing in the presence of high concentrations of
ammonia could be of value in the treatment of
wastewater, and an understanding of the anaerobic
oxidation of ammonia could lead to the development
of new chemical processes. The same organisms also
possess unusual metabolic intermediates such as hydrazine and produce unusual lipids which could also
be of value in the search for new chemical
intermediates.
Heterocyclic molecules containing sulfur, nitrogen,
and oxygen are among the most potent pollutants
and inevitably contaminate the marine environment
to a considerable extent. The use of microbes to
degrade and detoxify such compounds is gaining
considerable interest as a process which is environmentally friendly and would represent a long-term
solution to removing heterocyclic contaminants.
A particularly rich source of such organisms is the
marine environment where growth in close proximity to sulfur-rich hydrothermal vents or adjacent to
hydrocarbon (oil) seeps on the ocean floor has produced a plethora of microorganisms with metabolisms adapted to the utilization of a wide variety of
carbon-, nitrogen-, and sulfur-based chemistries.
Again, these organisms are also a very rich source of
enzymes with previously unknown characteristics
such as unusual substrate specificity, which could be
of great value to the chemicals industry where they
could be utilized in the production of new or
difficult-to-synthesize compounds because they can
perform reactions which are difficult to duplicate
using traditional synthetic chemistry methods.
Microbial Fuel Cells and Biofuels
The use of marine organisms to produce fuels has also
been proposed. The generation of electricity through
the degradation of organic matter has recently been
demonstrated to occur in marine sediments and may
be mediated by complex communities of marine
microorganisms. These organisms degrade complex
organic matter such as carbohydrates and proteins to
simpler molecules such as acetate which are then used
by electricity-generating bacteria to reduce metals
such as iron and manganese. By replacing the naturally occurring metals with an anode these bacteria,
under anoxic conditions, will supply the electrons
needed to produce an electric current to a cathode
linked to the anode by wires and exposed to the
oxygen in the water column. It has been suggested
that this type of system could be used to supply the
electricity needed to operate equipment in regions
where access is difficult and so eliminate the need
to replace batteries. Microbial fuel cells would be selfsustaining, would not require the preprocessing of
MARINE CHEMICAL AND MEDICINE RESOURCES 117